As many people as possible,
take part in food production.

So far, we have seen:

• Chemical fertilizers will rise structurally (Chapters 1–2)
• Industrial-style farming does not pencil out (Chapter 3)
• Don't aim for full self-sufficiency, but maintain domestic production (Chapter 4)
• Use soil microbes (Chapter 5)
• Rising CO2 is a tailwind (Chapter 6)

So how do we implement this in the real Japan?

First, one important recognition needs to be shared up front.

We are entering an era in which, unless as many people as possible grow at least some part of what they eat, society as a whole cannot produce enough food.

This is not moralism. It is a direct consequence of "industrial farming no longer pencils out," seen in Chapter 3. As full-time farmers exit because they cannot operate, domestic food production itself disappears unless someone fills the gap.

But, as confirmed in Chapter 4, this does not mean "everyone must become a full-time farmer." Different implementations at different scales — the full-time tan-no-hyakushō (one-tan smallholder farming), small-scale recovery of abandoned farmland, household balcony gardening — each carry food production at their own scale. Many people, a little at a time, each at their own scale. That is the realistic shape of food supply going forward.

7.1 In Japan, Large-Scale Farming Itself Becomes Impossible

In Chapter 3 we said "the books don't close on industrial farming." Pushing one step further:

Under fertilizer constraints, in Japan, large-scale farming itself becomes physically impossible.

It is not "we'll shrink because it isn't profitable." It is "even if you try, you can't" — that stage.

The reasons lie in conditions specific to Japan.

Without fertilizer arriving, large-scale farming does not run

As Chapters 1–2 showed, Japan depends on imports for roughly 90% of its chemical fertilizer. Phosphate, the raw materials for nitrogen, potash — almost all of it is imported. And those imports are structurally thinning.

Large-scale farming — the mechanized operation of several to dozens of hectares — is designed on the assumption of heavy chemical-fertilizer input. Sow seed densely, force growth with chemical fertilizer, suppress pests and disease with pesticides, harvest in one sweep with machines. That structure only works when fertilizer arrives cheaply and abundantly.

If the absolute supply of fertilizer falls, the very premise that supports large-scale operation disappears. "Halve the fertilizer, keep the scale" means a yield collapse. Where the soil microbiome has not recovered, take chemical fertilizer away and the crop does not grow.

Topography and the structure of farmland

Japan's farmland is small-scale and dispersed by origin. Mountainous, with many terraced rice paddies and stepped fields, with little of the continuous plain that exists in the United States or Ukraine. After the war, efforts were made to consolidate farmland into larger plots, but the topography places a hard limit on what can be done.

The economies of scale from mechanization also fail to bite as hard as they do in Europe and North America. Industrial farming nonetheless worked because of cheap fertilizer and machinery, and a division of labor with imported feed and imported grain.

If fertilizer becomes expensive and the effects of scale are limited, both the economic and the physical foundations for sustaining large-scale farming in Japan collapse.

Conclusion: the route of "ride it out by going larger" is closed

The prescription "if fertilizer is expensive, scale up and become more efficient" is the thinking of an era of cheap fertilizer. In a phase where the absolute amount of fertilizer is shrinking, scaling up means expanding costs; it does not avoid the fertilizer constraint.

Fertilizer constraint + Japan's topography + soaring imported feed = large-scale farming is unsustainable.

There is only one answer that comes out of this: return to small-scale and dispersed. Society as a whole shifts to food production in which many people are involved, each at their own scale.

But there is one important distinction to make here. We said "large-scale farming becomes impossible," but not all crops fail uniformly. What is decisive is whether the crop rides on mechanization or not. That is the next section.

7.2 Crops That Mechanize, and Crops That No Longer Will

Industrial farming, at its core, is mechanization. Tractors, combines, harvesters, automated irrigation, post-harvest processing — these machines, in place of human hands, produce food at volume. Chemical fertilizer and pesticides are designed integrally with mechanization.

That means, under fertilizer constraints and a shrinking labor force, what survives is

only the crops on which mechanization works.

Conversely, crops that don't ride mechanization fall outside the industrial mass-production frame. These become "must be grown by hand" crops.

This is the decisive distinction when thinking about crop choice and priorities for domestic production.

Crops that ride mechanization — those a combine can harvest in one pass

The core of mechanization is mechanized harvesting. Reaping a whole field in one pass with a combine, or digging it all up with a harvester — this has supported the productivity of industrial farming.

Mechanization works for:

For these crops, where broad plains and uniform fields can be secured, large volumes can be produced with few people. The U.S. Midwest, the Ukrainian black-soil belt, the Canadian prairies, the Australian wheat belt — industrial farming has worked on these conditions.

Even as fertilizer thins, those regions retain large-scale machinery, vast land, and relatively fertile soils as assets. Some level of production can continue (even if quality and quantity drop).

In other words, crops that ride mechanization will continue to be grown somewhere in the world. It will, for the time being, remain possible for Japan to keep importing them.

Crops that don't ride mechanization — those that need hands

The problem is the opposite case.

Most fresh vegetables and fruits resist mechanical harvest. Picking them one at a time by ripeness, without bruising, is hard for machines. Even today, these depend on human hands.

Worldwide, these crops depend on human hands. Even in the United States, fresh-vegetable harvest still relies on hands — largely on seasonal workers from Mexico (as we'll see in 7.3, the U.S. imports roughly 30% of its fresh vegetables, which is the very structure of "crops harvested by hand").

In Japan the conditions are even worse:

• Fields are small, terraced rice paddies and stepped fields are common — machines do not enter
• The labor force is aging and shrinking
• Wage levels are high; the cost model of hiring large numbers of seasonal workers does not hold

In short, even if you tried "industrial-scale mass production" of fresh vegetables and fruits in Japan, the structure does not exist for it in the first place.

Mechanization and regenerative agriculture — even "mechanizable crops" do not always coexist with both

One more layer of consideration is needed here.

The list of "crops that ride mechanization" above was written with 20th-century industrial farming in mind — mechanization that assumes the abundant use of chemical fertilizer and pesticides.

But as Chapter 8 will show, the principles of regenerative agriculture are no-till, no bare soil, never let the living roots die. The shape of mechanization does not always align with these.

What is decisive is whether harvest disturbs the soil.

Combine harvest — coexists with regenerative agriculture

A combine is a machine that cuts standing crops above ground.

• Wheat, barley, rye, oats: cut leaving 10–30 cm of stem at the base. Roots remain in the soil
• Rice (plains, paddy): similarly cut by combine. Roots remain
• Soy, beans, rapeseed, buckwheat: same
• Corn (grain): grain is taken from the standing stalk
• Forage and silage: simply mowed. If perennial, it regrows

For these, roots remain in the soil and residue returns to the surface. Sow the next cover crop and living roots quickly come back. Compatible with no-till.

In fact, Gabe Brown has continued no-till combine-harvested grain and soy for over 20 years and raised SOM (soil organic matter) from 1.7% to over 11% (Chapter 6). This is the textbook case of regenerative ag × mechanization × mass production succeeding.

Crops dug up by harvester — clash with regenerative agriculture

The problem is here.

• Potato: a potato harvester digs up soil 20–30 cm deep. Each year the topsoil of the entire field is disturbed
• Sweet potato: similarly dug up
• Onion: pulled or lifted, roots removed
• Sugar beet: pulled from depth by a deep-digging harvester
• Mechanically harvested carrots and daikon (large fields): same

For these, the very mechanization of harvest involves large-scale soil disturbance.

A field where potatoes are harvested mechanically every year is the same as a field that is "fully tilled" every year. The mycorrhizal network and the aggregate structure are destroyed every year. The microbiome cannot bear it.

The principles of no-till — do not destroy the microbial network, hold aggregate structure — are mutually exclusive with these mechanical harvests. Hand-digging at small volume coexists with regenerative agriculture (home garden / one-tan-smallholder level). But mechanized mass production does not coexist with regenerative agriculture.

Crops where the entire plant is cut or removed — intermediate

• Processing tomato: a machine grabs the whole plant, vibrates the fruit off, discards the plant. The living roots all die at once.
• Processing cabbage and lettuce: cut at the stem base. Roots remain, but the surface is easily left bare
• Mechanized onion mowing (the type that does not cut roots): closer to intermediate

These do not directly dig up the soil, but they tend to clash with the principle of never letting living roots die (Chapter 8). Sowing a cover crop immediately afterward enables recovery, but the management overhead increases.

And further — monoculture damage and rotation constraints

One more important constraint comes in here. Continuous-cropping damage.

Industrial farming has supported same-crop, same-field every year — or short rotations — through chemical soil treatment. Soil sterilization, fungicides, nematicides, chemical pesticides. By suppressing soil disease with these, monoculture has held.

Regenerative agriculture does not use these chemical treatments. Instead, it uses long rotations to dodge soil disease. This bears heavily, especially on the "middle" tier of crops.

Brassicas like cabbage and Chinese cabbage — clubroot, 5–7 year rotation

Brassicas (Brassicaceae) such as processing cabbage, broccoli, and Chinese cabbage carry the soil disease clubroot (Plasmodiophora brassicae).

• Once it appears, the spores survive in the soil for 5–10 years or more [unverified]
• Industrial methods have suppressed it with chemical fungicides and soil sterilization
• Regenerative agriculture cannot use these — the only countermeasure is to leave a 5–7 year rotation during which the field carries no Brassicas

In other words, to grow mechanized cabbage on a given field, you can grow cabbage there only once every 5–7 years. The rest of the time the field must carry other crops (grains, legumes, forage, or non-root crops).

Onion — long rotation due to white rot

Onion also carries the soil disease white rot (Sclerotium cepivorum). The sclerotia (resting bodies) are said to survive in the soil for over a decade to several decades [unverified].

This too, without chemical fungicides, requires a long rotation (7+ years). The structure of mechanized mass production of onions on the same field every year does not hold under regenerative agriculture.

Processing tomato — 3–4 year rotation

Processing tomato also accumulates soil diseases under monoculture — bacterial wilt, fusarium wilt, root rot. A standard rotation of 3–4 years is needed [unverified].

Tomato is not as severe as Brassicas, but even so, industrial-style yearly continuous cropping is not possible.

What the rotation constraint means

What follows from this constraint?

The "middle" tier of crops — processing cabbage, processing onion, processing tomato — cannot be grown on the same field every year under regenerative agriculture.

Mechanization itself is technically possible. But on a given field, they are actually grown only once every 3–7 years. The remaining years must rotate other crops.

What this means is:

• To maintain the same production volume requires land with rotation headroom — 3 to 7 times the area
• Effective production density per unit area drops sharply versus industrial
• Machinery also has long idle periods because of rotation — recovering machinery investment becomes hard

So technically these are "mechanizable," but economically, mass production becomes hard to sustain. These crops are likely, while not as severely as the "lower" tier (potato, etc.), to slip out of the large-scale mechanized framework in practice.

This rotation constraint must be accepted as the price of regenerative agriculture's long-term durability. You cannot grow at high density in the short term. In exchange, you can maintain a healthy soil that is not dominated by disease.

Industrial-style enabled monoculture through chemical treatment, but exhausted the soil ecosystem in return. Regenerative agriculture protects the soil through rotation, but gives up output per unit area. The choice isn't really between them — in an era when chemical treatment can no longer be used, only the latter remains.

And one more thing — these are also "crops whose yield falls without chemical fertilizer"

So far we have looked at two axes: "compatibility with mechanization under regenerative agriculture" and "monoculture damage and rotation." There is, in fact, one decisive axis remaining.

Chemical-fertilizer dependency.

An important distinction is needed here.

"Crops whose yield falls without chemical fertilizer" come in two stages.

Stage A: crops where the product itself does not exist without chemical fertilizer

This is especially marked in F1 hybrid vegetables.

• Cabbage, Chinese cabbage, broccoli (F1) — without nitrogen, head formation is incomplete and size is small. Even "the cabbage shape" doesn't form
• Onion (F1) — large requirement for N → P/K. Without chemical fertilizer, the bulb does not develop properly
• Processing tomato (F1) — large N, P, K, Ca demand. Fruit set is poor; fruit is small and few
• Processing potato (modern cultivars) — Russet Burbank (U.S. fries), Toyoshiro, Atlantic (chips), etc. Heavy demand led by K. Without chemical fertilizer, tubers do not reach the size and specific gravity (dry-matter ratio) the spec requires

Without chemical fertilizer, these do not take their product form. Even if you grow them, they don't make the marketable spec. It moves beyond "lower yield" to "the product does not exist."

In fact, in natural-farming practice, cabbage, onion, and F1 tomato are often called "hard for beginners" or "won't head until you've built good soil." This is empirical, but it aligns with the analysis above.

Stage B: crops where yield rises with chemical fertilizer but exists without it

To be distinguished are the grains.

• Modern wheat (short-stem high-yield cultivars) — bred for high nitrogen response, but heads still form under low input. Yield drops, but as a product, it stands
• Modern rice (Koshihikari lineage) — same. Biological nitrogen supply in paddies covers some of it
• Soy and pulses — self-fix nitrogen via rhizobia; bred from origin for low input

In fact, large-scale no-till and cover-crop operation of modern wheat is widely practiced around the world.

• Gabe Brown (North Dakota): modern wheat and soy, no-till and cover-cropped for over 20 years, SOM raised from 1.7% to 11% (Chapter 6)
• Australia: over 80% of total wheat acreage is no-till [unverified]
• Argentina, Canadian prairies: similarly large-scale no-till and cover-crop grain operations
• Rodale Institute's 40-year long-term trial: organic wheat yields reached parity with conventional [unverified]

In other words, modern wheat clearly works under regenerative agriculture × mechanization × at scale. Just because it's a green-revolution cultivar doesn't mean it's chemical-fertilizer-only. Add nitrogen and you get maximum yield, but heads still form without it. Cover crops (legumes) supply N, rotation dodges disease, no-till maintains soil — that combination keeps scale.

However, modern corn is different

Modern corn (dent corn, sweet corn F1) has an unusually large nitrogen demand even among grains, and yield decline under low input is pronounced. Cover-cropping and rotating with legumes covers it partially, but not as well as for modern wheat. Within the green revolution, corn is more accurately treated as "an extreme nitrogen-dependent crop."

Dependency comes in stages

The crops hard to grow under natural farming are mainly Stage A. Stage B works at scale with proper regenerative-agriculture management (cover crops, rotation, no-till, mycorrhizal use). Stage C grows on low input from origin.

Why grains and legumes work at low input — symbiosis with mycorrhizal fungi

There is a botanical basis for this. As Chapter 5 showed, many plants have the capacity to symbiose with mycorrhizal fungi (mycorrhiza) and receive phosphorus, nitrogen, and minerals from the soil — the mechanism by which microbes carry nutrients even without chemical fertilizer.

And this symbiotic capacity differs greatly between plant groups.

Grasses (Poaceae) (rice, wheat, barley, corn, rye, millets, forage grasses)

• Strongly form arbuscular mycorrhiza (AM)
• Most grasses gather phosphorus, water, and trace elements efficiently through the mycorrhizal network
• This is an evolutionarily deep symbiosis, in place long before chemical fertilizer existed

Legumes (Fabaceae) (soy, adzuki, kidney, peas, clover, milk vetch, alfalfa)

• In addition to AM mycorrhizal symbiosis, fix atmospheric nitrogen directly through symbiosis with rhizobia
• That is, double biological nutrient supply — phosphorus and trace elements via mycorrhiza, nitrogen via rhizobia
• Rotating legumes as a cover crop leaves nitrogen in the soil, and the next grain crop benefits

So grains and legumes are evolutionarily built to "outsource to soil microbes." Even without chemical fertilizer, mycorrhiza and rhizobia deliver nutrients. They mesh biologically with regenerative agriculture's no-till, low input, and cover crops.

Gabe Brown's no-till operation in North Dakota, Australia's no-till wheat belt, prewar Japanese rice cultivation — all of them, in effect, drew on the power of grass and legume mycorrhizal/rhizobial partnerships.

This is the basis directly connecting to Chapter 5 (the soil-microbe strategy).

Brassicaceae and Chenopodiaceae botanically do not symbiose with mycorrhizal fungi

The reverse — why the Stage A crop group depends so strongly on chemical fertilizer — has its root here too.

Brassicas (Brassicaceae) such as cabbage, Chinese cabbage, broccoli, cauliflower, daikon, and turnip are a plant group that scarcely symbioses with mycorrhizal fungi [unverified: botanical fact]. This is botanically established; Brassicaceae is one of the few families that largely lost mycorrhizal symbiosis over evolutionary time.

As a result:

• They cannot collect soil phosphorus or trace elements via the hyphal network
• They can only use nutrients within direct reach of their own roots
• To secure nutrients, they must be supplied externally in volume — chemical-fertilizer dependency rises by necessity
• Continuous-cropping damage (clubroot) also spreads easily in soils that lack mycorrhizal-network protection

So Brassicas are biologically "ill-suited to natural farming." F1 breeding has driven them further into a chemical-fertilizer premise, but the underlying dependence is in the plant family itself.

The Amaranthaceae (Chenopodiaceae) family of spinach and sugar beet is similarly known not to symbiose with mycorrhizal fungi. These too fall into the category of "hard to grow under natural farming."

Improved cultivars have converged on the same pattern

A note here on the historical structure of cultivar improvement.

F1 cabbage, F1 onion, F1 processing tomato, processing potato — these are different crops, but the direction of breeding is strikingly similar.

• Selected for mass, uniform, spec-grade product
• Bred to give maximum yield and uniformity under high-fertilizer input
• Selected for traits that withstand large-scale mechanical harvest (cabbage: simultaneous heading, onion: simultaneous toppling, tomato: simultaneous coloring, potato: simultaneous bulking)
• The result: a constitution that performs only on the premise of large external chemical-fertilizer inputs

Late 20th-century breeding advanced as one body with chemical fertilizer, pesticides, and mechanization. "Improved" was almost synonymous with "optimized to industrial farming." The wheat and corn cultivars of the green revolution are the archetypes, but vegetables and tubers underwent the same convergence.

As a result, processing potato cultivars, F1 onion, F1 processing tomato, and F1 Brassica vegetables — though different crops as such — resemble each other like siblings in their chemical-fertilizer dependency. Treating them together as "Stage A" rests on the historical structure of cultivar improvement.

Conversely, return to heirloom (traditional) varieties and you can grow them, after a fashion, on low input.

• Heirloom potato (Andean lineages, older cultivars like May Queen): yields fall, but tubers do form on low input
• Heirloom cabbage (loose-heading types, older European cultivars): the head is loose, but it is still edible
• Heirloom tomato (open-pollinated, home-garden suitable): less uniform than F1, but grows on low input

So the Stage A crop group can, to some extent, be grown by "returning varieties to heirloom" + "intercropping and rotation" + "harvest by hand." But the volume is, as the next section shows, on the order of 5–10% of industrial output.

Growing Brassicas and Chenopodiaceae under natural farming — Brassica intercropping and rotation, but production drops drastically

We said "Brassicas and Chenopodiaceae are hard to grow under natural farming," but it is not zero. There are ways to grow these non-mycorrhizal crops without external chemical-fertilizer input. But the scale becomes orders of magnitude smaller.

There are two main means.

1. Intercropping (companion planting)

Plant strongly mycorrhizal partners — grasses, legumes — on the same ridge as, or on adjacent ridges to, Brassica or Chenopodiaceae crops.

• The mycorrhizal network spreads from the surrounding grass and legume roots
• Nitrogen fixed by legumes circulates in the soil to other plants too
• Brassicas do not bind directly to mycorrhiza, but benefit indirectly via root-exudate-mediated nutrient cycling from a soil with high surrounding mycorrhizal activity
• Pest disorientation also adds (it becomes harder for cabbage white butterflies and the like to find cabbages)

Examples:

• Cabbage + clover (legume)
• Cabbage + cereals (grasses)
• Spinach + carrot (Apiaceae) + lettuce (Asteraceae) mixed sowing
• Cabbage + nasturtium (flower) for pest control

This is a method long known in traditional European home gardens, in Japanese heirloom plots, and in permaculture practice.

2. Crop rotation

Separate the years that grow Brassicas / Chenopodiaceae from the years that recover the soil.

As an example, one 7-year rotation:

In this case, cabbage can be grown only once every 7 years. The remaining 6 years another crop uses the same field.

Result — production drops to 5–10% of the industrial scale

With intercropping and rotation, you can indeed grow Brassicas and Chenopodiaceae without chemical fertilizer. But when you do the math:

• Brassica yield per unit area drops to roughly 30–50% of industrial (spacing under intercropping, low-input growth) [unverified]
• In rotation, Brassicas are actually grown only once every 5–7 years
• The result: annual Brassica production across the field is on the order of 5–10% of industrial

In other words, growing these crops under natural farming is possible, but the volume is orders of magnitude smaller.

If society as a whole tried to maintain cabbage, onion, and spinach at industrial-equivalent scale, 5–10× the farmland would be needed. In Japan that is impossible (it would exceed total arable land).

Three-axis summary — mechanization × regenerative agriculture × chemical-fertilizer dependency

Re-evaluating the discussion so far on the three axes of "mechanization × regenerative agriculture × chemical-fertilizer dependency":

The crops graded "hard to grow" face

• yield drop as chemical fertilizer rises (fertilizer constraint)
• conflict between regenerative-agriculture principles and mechanization
• lower production density due to rotation
• F1 seed supply itself riding on a chemical-fertilizer premise

— compound pressures. These are crops that become hard to grow both under industrial and under natural farming.

Production volume of these crops at the social level can only move, in the long run, in one direction: down.

The table itself changes structurally

What follows is the prospect that the table itself shifts structurally.

The structure under which Stage A crops have been mass-supplied cheaply — based on chemical fertilizer, large-scale mechanization, and monoculture — thins.

• Processing tomato (ketchup, pizza sauce, canned tomato)
• Processing cabbage (frozen vegetables, salad mix)
• Onion (the base of all kinds of processed food)
• F1 hybrid leafy vegetables
• Potato (modern cultivars, for processed food)

These move toward being unable to be sustained at present prices and volumes.

Meanwhile, grains, soy, and forage sustain mass production even as the world transitions to regenerative agriculture. Modern wheat, soy, and forage no-till operation in the U.S., Canada, Australia, and Ukraine already works at large scale. The main parts of the Japanese table —

• rice, wheat products (bread, noodles)
• soy products (miso, natto, tofu, soy sauce)
• forage-based livestock products (dairy, pasture-raised meat)

— can be sustained under the natural-farming and regenerative-agriculture frame.

And the things easy to grow under natural farming —

• millets, traditional grains
• sweet potato, traditional root crops
• seasonal mountain vegetables, herbs
• seasonal fish, mushrooms and tree nuts gathered from the mountain

— gain relative weight.

Overall, the table is reorganized from the postwar structure centered on "Stage A F1 high-fertilizer-eating processed foods" toward a more unadorned structure of grains + legumes + root crops + seasonal vegetables. As a side effect, it approaches the era before the postwar diet began — the basic structure of traditional Japanese food.

The wartime British example mentioned in Chapter 4 was the same pattern. The improvement of British nutrition under rationing came from lowering dependence on processed meat and processed wheat and raising dependence on root crops, legumes, dairy, and grains. "Volume going down" and "nutrition going down" are not the same thing.

The era when chemical fertilizer, mechanization, and monoculture all worked at once will end with that era. What remains is a more unadorned, but nutritionally sufficient, core of traditional food.

This is not just a Japanese story — a global vegetable shortage will occur

The analysis so far has been written in the Japanese context, but the elements composing the logic are all global.

• Chemical-fertilizer supply constraint (China's export controls, low-grade ores, the sulfur problem) — global
• High fertilizer dependency of improved cultivars — common across the world's commercial farmland
• Brassicaceae and Chenopodiaceae not symbiosing with mycorrhizal fungi — botanical fact
• Soil disturbance from mechanization, monoculture damage — physical and ecological fact

In other words, the phenomenon of Stage A crops (F1 cabbage, onion, processing tomato, processing potato, etc.) becoming impossible to mass produce will happen everywhere in the world.

The same pressures fall in the U.S., in Europe, in Mexico, in China.

The structure of the global vegetable shortage

Concretely, what happens?

1. Production drops in the major producing regions

• California (lettuce, broccoli, processing tomato): water-resource constraint + fertilizer constraint
• Mexico (winter vegetables for the U.S.): same fertilizer constraint
• Spain, Netherlands (vegetables for Europe): same
• China (the world's largest vegetable producer): self-priority + fertilizer constraint

2. Export capacity disappears

Each country prioritizes the food supply of its own people. The volume available to export drops. Even the U.S. imports about 30% of its fresh vegetables (as we'll see in 7.3) — if that source (mostly Mexico) thins, U.S. supermarket shelves lose winter vegetables.

3. Seasonally shipped vegetables collapse first

Winter fresh vegetables carried from warm regions (Mexico, southern Europe, North Africa) — which depend on fertilizer + transport + labor + mechanization all at once — thin first, structurally.

Each region is forced back to seasonal vegetables it can grow at home.

4. Prices rise globally

If supply thins, world-market vegetable prices rise. It hits Japan's imported vegetable prices directly.

Japan's options are limited

If world vegetable supply thins everywhere, even saying "import what falls short" approaches a state where there are no vegetables to buy, or prices are orders of magnitude higher.

The strategy "make up the shortfall through imports," confirmed in Chapter 4, holds for

• grains, legumes, livestock products: holds (grasses and legumes will continue to be grown worldwide under regenerative agriculture × mechanization)
• vegetables, fruits: becomes hard to hold (Stage A crops thin globally; non-mechanized crops are short of hands worldwide)

We have to grow them domestically by hand. And that is only possible through food production in which many people are involved, each at their own scale.

The proposition "as many people as possible take part in food production" is not just about Japan's food security. It is also the only realistic answer to the global vegetable supply constraint.

When the same pressure falls everywhere at once, no country can simply import its way out. Each country, region, and community shifts toward growing by hand at home. This is not a Japan-specific challenge but part of a global redistribution of food production.

7.3 Imports Carry Us For Now — But Not Forever

While domestic large-scale farming shrinks and the transition to small-scale, dispersed production takes time, how do we fill the gap?

There is only one answer. For now, we ride imports.

Fortunately, the world has countries with farmland far richer than Japan's. The U.S. (Midwest plains), Ukraine (black-soil belt), Canada, Australia, Brazil — these countries possess

• continuous plains
• fertile topsoil (Ukraine's black soil is among the world's best)
• topography suited to mechanization
• yields possible with smaller fertilizer inputs from origin (smaller than Japan's)

The fertilizer constraint affects everyone, but the richer the soil to begin with, the lighter the relative impact. Some countries are not built such that taking fertilizer away triggers yield collapse, as Japan is.

So for the next several to ten-plus years, supporting Japan's table through imports from these countries is itself a realistic choice. There is no need to deny it.

In the transition period as industrial farming collapses, imports function as society's cushion. Using them is itself realistic and rational.

But it doesn't continue forever. And the assumption that "exporting countries grow it all themselves" is in fact not true.

Even the U.S. imports vegetables

It may come as a surprise, but the world's largest agricultural country, the United States, imports a substantial share of its vegetables.

According to USDA statistics:

• About 30% of fresh vegetables in the U.S. are imported [unverified: exact figure and year]
• About 50% of fresh fruit is imported [unverified]
• Main sources: Mexico (tomato, pepper, cucumber, zucchini, berries, etc.), then Canada, Guatemala, Costa Rica, Peru, etc.
• Import share is especially high in winter (when the U.S. mainland is too cold to grow vegetables)

In other words:

The U.S. is an export superpower in grains, soy, and meat, but also an import superpower in vegetables and fruit.

This shows that modern food supply is divided globally. Even the U.S. with its fertile plains does not grow everything down to the vegetables itself. Because it is more rational to ship winter vegetables from warmer Mexico or Central America, that is what is done.

Australia and European countries are in similar shape. There is practically no country in the modern world that "fully self-supplies its own food."

What this fact shows

Two things follow.

One: Japan is not uniquely strange

The argument that "Japan's food self-sufficiency is low" often paints Japan as an anomaly. But modern food supply is globally woven from the start. The U.S., Europe, and Canada all import what they cannot grow. Japan's reliance on imports is, in itself, the normal shape of modern food systems. The problem is that we are entering a phase where the stability of imports is collapsing, not that imports themselves are bad.

Two: but the web is thinner than you think

Just as the U.S. imports vegetables from Mexico, each country's food supply is composed of a thin, mutually dependent web. Climate, war, trade friction, currency, energy prices — break any one and the web breaks somewhere.

If the U.S. cannot pull vegetables from Mexico, U.S. supermarket shelves may lose winter vegetables. The U.S. tries to buy from other countries. World-market vegetable prices rise. Aftershocks reach Japan.

Food is connected from origin to table by a long, hard-to-see web. In peacetime the web works. But it breaks easily.

Four reasons imports cannot last forever

Reason 1: exporting countries also turn inward

The same dynamic seen in China's export restrictions in Chapter 1 can happen with food. Neither the U.S. nor Ukraine has any obligation to keep exporting if it threatens their own people's food security. A shock — climate, war, regime change, disease — triggers export restrictions; the volume reaching Japan drops sharply.

This has happened many times before. The U.S. soy export ban (1973), Russia's wheat export restrictions (2010), the halt of grain exports from Ukraine due to the war (2022) — food exports are merely a peacetime structure; in crisis they stop.

Reason 2: the fertilizer constraint is global

It is not just Japan facing rising fertilizer costs. The U.S., Europe, and emerging economies all face the same. As the books fail to close on industrial farming worldwide, the production volume of exporting countries themselves drops. Less to sell means higher prices.

Ukraine's black-soil belt is indeed rich, but war and geopolitical instability have been added. And as energy and fertilizer prices rise in the U.S., its export capacity drops too.

Reason 3: geopolitics and shipping

Food comes by ship. Strait of Hormuz, Strait of Malacca, Suez Canal, Panama Canal — anything happens to these routes and food stops too.

Middle East situation, South China Sea, Taiwan Strait, Arctic routes — 21st-century geopolitics does not guarantee the stability of food shipping. The premise "if you pay, it comes" is a peacetime one.

Reason 4: prices squeeze household budgets

Even if you can physically import, the constraint comes in the form of prices hitting households directly. Imported meat, imported wheat, imported soy, imported feed — if they double or triple, diets begin to fall apart from the lower-income tier.

"Can be imported" and "ordinary households can afford it" are different things.

The time imports continue is the grace period for transition

The conclusion that follows is:

The time imports continue is the grace period for standing up dispersed food production.

While imports continue, we need to:

• complete full-time farmers' transition to microbe-based agriculture
• launch small-scale production by retirees and migrants
• advance recovery of abandoned farmland
• expand balcony gardening and community gardens for urban households
• build up seed banks, distribution networks, and regional infrastructure

We need to make these things in time.

If we start in a panic when the import tap thins, we are too late. Soil-building takes years (the Gabe Brown case in Chapter 6). On a field where the soil isn't ready, even starting suddenly will produce no yield in the first few years.

So:

• now is the era when "imports are still arriving"
• but that time is not time to do nothing —
• it is time to use to transition to the next regime.

This is the heart of the realistic strategy that combines imports with domestic production.

7.4 "As Many People As Possible, At Whatever Scale They Can"

So who grows, and how much?

The answer is:

As many people as possible, working at whatever scale they can.

Concretely:

• Full-time farmers stay full-time, but transition away from chemical-fertilizer dependency
• Retirees, side-business holders, and migrants begin small-scale production around one tan
• Urban households grow part of their vegetables on balconies and in community gardens
• Schools, companies, and NPOs hold plots as education / training / community activity
• Restaurants, inns, and welfare facilities secure part of their ingredients from their own plots

Every layer takes part in food production at a scale that suits them without strain. Each individual scale is small, but stacked across society as a whole, it becomes a pillar of the food supply.

This is not the rhetoric of "the ideal of self-sufficiency." As confirmed in Chapter 4, we do not aim for full self-sufficiency. There is feed and fuel headroom on world markets, and we can cover the shortfall with imports — but only, as 7.3 showed, for now.

This is not a story of "domestic production can be zero." In a phase of shrinking full-time farmers, unless someone grows in their stead, domestic production itself disappears. Imports and domestic production both have to exist before the food supply stabilizes.

It is not "everyone becomes a farmer." It is "many people, each at their own scale, grow something." Each person small, summed across society into a pillar.

This is the realistic dispersed strategy in a phase where industrial farming collapses.

7.5 Masanobu Fukuoka's "One-Tan Smallholder" — The Minimum Unit at Personal Scale

As a scale anchor, there is the tan-no-hyakushō (one-tan smallholder farming) idea proposed by Masanobu Fukuoka.

One tan is about 10 ares, that is, 1,000 square meters. About 30 m × 33 m.

From years of practice in Iyo, Shikoku, Fukuoka stated [unverified: exact quote]:

If you have one tan of paddy and one tan of dryland field, that is enough for a family's rice and vegetables.

This claim sounds too small by the standards of postwar agriculture. Conventional full-time farmers ordinarily cultivate 1 hectare (10 tan) or more. One tan looks like an extension of a "home garden."

But what Fukuoka was saying is different.

• No-till, no-weeding, no-fertilizer, you can run a rice-and-wheat double crop
• Once the soil becomes fertile, yield comes out comparable to conventional
• No machinery, so cost is almost nothing
• One tan covers a family's staple food

If true, the economic-model implications are large.

The economics of one tan

Let's think about it in modern numbers (rough order of magnitude).

[All figures are rough; unverified]

Yield is below industrial. But cost is also lower. From the standpoint of "growing only what a family eats," the lower cost is what tells.

As "commercial crops," it makes less money than conventional. As "family food," it costs much less than conventional.

Implementation at this scale carries strong meaning as a hedge to secure food for yourself and your family by yourself.

And at the social level, the existence of countless one-tan-scale producers becomes a pillar that compensates for the decline of full-time farmers.

7.6 Using Abandoned Farmland — The Reality in MAFF Statistics

In Chapter 3 we touched on Japan's abandoned farmland. Let's confirm the precise definitions based on MAFF's most recent statistics.

[source: MAFF (Ministry of Agriculture, Forestry and Fisheries) statistics, 2024–2025]

What deserves attention is the fact that, by MAFF's strict definition of "recoverable (recoverable through ordinary agricultural work)," degraded farmland is 98,000 ha as of the most recent FY2024 data. The widely cited figure of "420,000 ha" likely refers to a "total area" of cumulative historical degraded farmland, which adds to the "recoverable farmland (98,000 ha)" the "non-recoverable degraded farmland" (where forest succession has progressed to the point that ordinary agricultural work can no longer recover it).

That said, this definitional drift does not undermine the logic of this series' argument. Rather:

Even land that, from the conventional industrial-farming view, is seen as "hard to recover (requires massive earthworks costs and large chemical-fertilizer input)" because it is reverting to forest can, by applying the framework of Tony Rinaudo's FMNR (Farmer Managed Natural Regeneration; using the cut stumps for natural recovery) or Masanobu Fukuoka's natural farming (a no-till, no-weeding approach that uses natural succession), be gradually used as an ecological production base without injecting massive capital.

Add to this that Japan's average per-operation farmland is 3.6 ha (2.6 ha in the prefectures) — extremely small — which shows it is structurally unsuited to the U.S.-style industrial monoculture that presupposes huge machinery and large chemical-fertilizer input. This physical constraint paradoxically supports the validity of the "tan-no-hyakushō (around 0.1-hectare-scale micro-agriculture) model" proposed in this series.

On small-scale, dispersed farmland, an operational principle that pushes external inputs (purchased costs) toward zero and treats "things not done (no weeding, etc.)" as a rational economic choice makes profound sense as a localized survival strategy in a high-cost era.

Such abandoned farmland is, under current industrial farming, land on which "there is no economic rationale to recover." So it is abandoned.

But from the microbe-based-farming view, it looks different.

• No tilling, no chemical fertilizer used, so initial investment is low
• Recovering the soil microbiome takes a few years (time-consuming, but not money-consuming)
• The small fields in mountainous areas are blessed with diverse plant communities to begin with
• Even where machines cannot enter, hands can manage just fine

In short, land that does not fit the scale of industrial farming comes back to life at the scale of microbe-based farming.

The same structure has played out before. Japan's satoyama (village mountainsides) was long "abandoned because it didn't pay economically." But it has come to be re-evaluated in the context of renewable energy (firewood, woody biomass), tourism, and education. The value of land changes with the economic model used to measure it.

Abandoned farmland is the same. A liability under the industrial model; potentially an asset under the microbial model.

Who does it

Recovering abandoned farmland is not something only full-time farmers do.

• Retirees with two-region living
• Young families migrating from cities
• Mid-career people doing it as a side business at small scale
• NPOs, citizen groups, educational institutions
• Groups combining it with satoyama conservation

These actors recover, each at a manageable scale, a little at a time. There is no need to recover the whole country at once. It is enough for it to grow gradually on a 10-year scale.

But late is also bad. The longer abandoned farmland sits, the more it returns to forest. The cost of recovery rises with time. Those who can move are rational to start moving now.

7.7 Balcony Gardens and Small Urban Spaces

At an even smaller scale, there are levels like balcony gardening, rooftop gardens, and community gardens.

"Growing vegetables on a balcony — what difference can that possibly make?" That's the urge. True, this is not a story about volume. It is only some percentage of a family's vegetables.

But this is where there is important meaning.

Meaning 1: the only scale where many households can take part

Few can become full-time farmers. Few can hold a one-tan field. For the majority of households living in apartment buildings in cities, the only scale they can take part in is the balcony or the community garden.

If we don't move here, the majority of households remain entirely disconnected from food production. That thins the floor of society's production capacity.

Meaning 2: a place to learn microbe-based agriculture skills

Even in a balcony planter, you can observe soil microbe behavior. Use compost, never let the living roots die, don't use chemical fertilizer — these principles can be acquired at a small scale.

In the future, when someone steps into one-tan smallholding, or recovers abandoned farmland, the skills learned here pay off. The balcony is also an entry to larger scales.

Meaning 3: a household cushion against rising prices

As imported and domestic vegetable prices rise, even producing cucumbers, tomatoes, herbs, and leafy greens on a balcony gives the household a cushion.

In particular, easily damaged leafy items (lettuce, salad greens, basil, mint, shiso) are expensive to buy at the supermarket but easy to grow in small amounts on a balcony.

Meaning 4: rebuilding the relationship between food and farming

This is a side that does not show up in the numbers but cannot be ignored.

When children and adults physically experience where their food comes from, it has long-term meaning. They come to know — not in their heads but in their hands — that food comes from nature, that soil and microbes grow it.

This raises society's understanding of food and farming policy across the board.

7.8 Full-time, Side, Self-sufficient — All Three Layers Are Needed

Organizing the implementation by scale:

What I want to emphasize here:

If any layer is missing, food production at the social level does not stand.

• If the full-time layer disappears, stable supply volume is lost
• Without the side / small layer, the decline of full-time cannot be filled
• Without the self-sufficient / supplementary layer, the majority of households are cut off from food production

In the era of industrial farming, only the full-time layer was needed. That was because of chemical fertilizer, imports, and population growth. After those conditions break, only when all three layers are stacked together does the food supply hold.

Not the same person needs to do every layer. Full-time farmers do full-time, side-job holders do side, households do household — each in a form that fits their own scale. But if the majority remain people who do nothing — pure consumers — society collapses.

7.9 Transition Timeline

It takes time to move from soil that depended on chemical fertilizer to the soil of microbe-based agriculture. But choose the method, and that time can be shortened drastically.

The mistaken single-crop transition (removing chemical fertilizer while staying single-crop)

• Year 1: yield drops sharply
• Years 2–3: mycorrhiza not rebuilt, yields stay low
• Years 4–5: signs of recovery at last
• Years 5–10: returns to conventional level

This requires a long, harsh "endurance" period.

Multi-species cover cropping (the right transition)

Intercrop grasses + legumes + resilient crops + diverse cover crops:

• Year 1: legume rhizobia fix nitrogen; grasses rapidly stand up the AM (arbuscular mycorrhizal) network
• Year 2: hyphal networks spread, beginning to mobilize accumulated phosphorus (legacy P)
• Year 3: soil microbiome functionally recovers, yields return to practical levels
• Year 4 onward: soil continues to enrich, yield and quality stabilize
• Year 10 onward: reaches levels above conventional farming (Gabe Brown's SOM 1.7% → 11% took 20 years, but productivity exceeded conventional in 5–10 years [unverified])

"Short-term yield-collapse risk" depends on the method of transition. If multi-species cover cropping rapidly stands up the biological network of mycorrhiza and rhizobia, you can return to practical levels in 3 years. The "endurance period" can be minimized.

Empirical data on the transition penalty

"Yields fall in the first few years when chemical fertilizer is abruptly halted" — this phenomenon is widely recognized as the transition penalty and demonstrated in large meta-analyses.

Pittelkow et al. 2015 meta-analysis (48 crops, 63 countries, 610 studies), based on observational data of 5,463 paired-years drawn from 610 studies covering 48 crops in 63 countries:

• The transition to no-till brings a clear yield drop in the early period
• Cotton seed yield under no-till was 6%–20% lower versus conventional tillage; on degraded soils starting from a degraded baseline, the yield penalty reached up to 25%
• Crop height was 9–13% shorter

Importantly, this initial yield drop on transition cannot be overcome simply by adding more chemical fertilizer. The root cause is physical and biological soil dysfunction, and what resolves the root cause is diverse cover crops.

Dramatic acceleration of recovery via diverse cover crops

Conventional fallow (bare soil) and reliance on single-species green manure (monoculture cover crops) require 3–6 years or more for biological soil function to recover. But in recent years, strong scientific evidence and field data have accumulated showing that using highly diverse multi-species cover cropping can dramatically shorten this biological lag and recover the soil ecosystem to a practical and economic level in about 3 years.

The mechanism at the core of the acceleration is the niche complementarity generated by plant-species diversity, and the explosive activation of the soil microbiome that comes with it.

Niche complementarity through four functional groups

Sowing and growing several different plant functional groups in the same field at the same time exerts strong "niche complementarity" spatially and functionally in the soil.

When these plant groups with different functional traits grow at once, biomass production and underground carbon supply that exceed the sum of their solo cultivations are achieved — the "transgressive overyielding" phenomenon — and the speed of soil-function recovery multiplies in synergy.

Quantitative data on "3-year recovery"

Multiple empirical studies confirm that combining cover cropping, no-till, and integration of livestock yields very clear numerical results in the recovery of core soil function within 3 years.

The hypothesis that "with diverse cover crops, even broken soil recovers in about 3 years and the transition penalty can be overcome" is not conceptual idealism; it is strongly supported quantitatively by rigorous scientific meta-analyses, long-term field demonstrations, and the vast data of pioneering regenerative-agriculture farmers.

Economic data: regenerative ag vs conventional farming

Empirical research on corn-production systems in the U.S. Northern Plains:

• Conventional farming, strongly dependent on insecticides and chemical fertilizer, has a pest incidence 10× that of the regenerative model that does not use insecticides
• A vicious cycle leading to further escalation in chemical-symptomatic costs
• Even though fields adopting regenerative systems had grain yields 29% lower than conventional, final profit was 78% higher
• This profit increase correlates directly not with maximizing yield, but with "a dramatic reduction in input costs" that comes with the rise in soil particulate organic matter (POM)

Under fertilizer inflation, the structure of "costs eat profit" is already quantitatively proven.

This timeline must be considered overlaid with the time imports continue.

As 7.3 showed, imports continue for now. But not forever. Standing up domestic dispersed production before the import tap thins is the social schedule.

"Transition once chemical fertilizer is high" is too late. "Begin farming once imports stop" is even later. Starting now and completing the transition over 3–5 years is the realistic schedule.

The same applies to new entrants. Whether starting tan-no-hyakushō, recovering abandoned farmland, or starting a balcony garden, the first few years are a learning and soil-building period. Starting in a panic when price spikes and supply constraints hit will not produce a harvest that year.

Expanding the carriers of food production is the kind of issue that won't be in time unless we move now.

7.10 Chapter 7 summary

The crop structure

• Under fertilizer constraints, large-scale farming itself stops working in Japan
• Crop evaluation runs on the three axes of "mechanization × regenerative agriculture × chemical-fertilizer dependency"
  • Producible at scale under natural farming: rice, grains in general including modern wheat, soy and pulses, forage — combine / mower harvest above ground, roots remain. Grasses (Poaceae) symbiose strongly with mycorrhizal fungi; legumes (Fabaceae) with mycorrhizal fungi + rhizobia — biologically built for low input. Demonstrated by Gabe Brown, Australia, Argentina
  • Thinning under compound pressures: F1 processing cabbage, onion, F1 tomato, F1 leafy vegetables, processing potato (modern cultivars) — Stage A, where removing chemical fertilizer breaks the spec. Improved cultivars have converged in similar shapes optimized for chemical fertilizer, mechanization, and mass-spec uniformity. Brassicaceae and Chenopodiaceae botanically do not symbiose with mycorrhizal fungi — biologically destined for external-nutrient dependence. Even with intercropping and rotation, production volume is on the order of 5–10% of industrial scale
  • Hand-dependent from origin: leafy vegetables, fruits, specialty crops — domestically, only growable by many people each at their own scale
• The table reorganizes from the postwar structure centered on Stage A toward the more unadorned structure of grains + legumes + root crops + seasonal vegetables (approaching the basic structure of traditional Japanese food)
• This is not just a Japanese story. Vegetable supply thins globally (the U.S., Mexico, Europe, China face the same pressure) — no country can simply import its way out

The implementation structure

• For now, ride imports from countries with rich farmland — the U.S., Ukraine, etc.
• But that is not infinite. The time imports continue is the grace period for transition
• Leaving it to full-time farmers alone cannot maintain domestic food production
• Only when the three layers — full-time, side, self-sufficient — all stack does it stand
  • Full-time (pro farmers, several tan to several ha): commercial crops, regional core
  • Tan-no-hyakushō (migrants, side-job holders, retirees, around one tan): family staple + selling surplus
  • Balcony / community garden (general households): the only scale the majority of households can take part in, household cushion, education, place to engage
• Abandoned farmland is a liability under industrial, potentially an asset under microbial
• A society of pure consumers alone can no longer grow food
• Transition with multi-species cover cropping completes in about 3 years (the mistaken single-crop transition that just removes chemical fertilizer takes 5–10 years; choose the method and you can shorten it)
• Therefore, starting now, while imports continue, is realistic

The direction of implementation by scale is clear. Next, specific operating principles — what to do, what not to do — follow.

In the next, final chapter (Chapter 8), we summarize the operational principles: no-till, no bare soil, diversity, no weeding, no chemical fertilizer, self-saved seed, considerations for storage and distribution. And we present the conclusion of the entire series.

References

Transition penalty / meta-analyses

• Pittelkow et al. 2015 meta-analysis (48 crops, 63 countries, 610 studies, 5,463 paired-years) — global meta-analysis of the transition to no-till
• Knapp & van der Heijden — meta-analysis of temporal stability under organic agriculture
• "Regenerative agriculture: merging farming and natural resource conservation profitably" — PMC5831153

3-year recovery via diverse cover crops

• Weber & Gokhale (2011) — water retention +54% under holistic grazing management (after 3-year treatment)
• Long-term empirical platform research — WSA (Water-Stable Aggregates) from moderate 34.1–50% to 66%+
• Soil Health Academy / Dr. Allen Williams — carrying capacity 5× (3 years)
• Datu Research / Willis Farm case study, Missouri, USA — net profit +$17/acre in 3 of 4 years
• Plant-ecology literature on niche complementarity
• Literature on the roles of the four functional groups (grasses, legumes, Brassicas, broadleaves)

Economic data: regenerative vs conventional

• U.S. Northern Plains corn-production system empirical research — conventional has 10× the pest incidence of regenerative; regenerative has yield -29% but profit +78%
• Research on input-cost reduction associated with rising particulate organic matter (POM)

Pioneers: Gabe Brown

• Gabe Brown, Dirt to Soil: One Family's Journey into Regenerative Agriculture (2018) — multi-dozen-species cover-crop cocktails, SOM 1.7% → 11%

Structural data on Japanese agriculture

• MAFF (Ministry of Agriculture, Forestry and Fisheries) statistics (FY2024–2025)
  • Total arable land nationally 4.239 million ha (2025)
  • Recoverable degraded farmland 98,000 ha (FY2024)
  • Operating area per farm operation 3.6 ha (prefectures 2.6 ha; Hokkaido 33.7 ha)
• Historical trend of abandoned-farmland statistics (210,000 ha in 2000 → 420,000 ha in 2020)

U.S. agricultural-import data

• USDA import statistics — about 30% of fresh vegetables imported (mainly from Mexico); about 50% of fresh fruit imported

Coexistence of mechanization and regenerative agriculture

• Equipment specs of potato harvesters, onion harvesters, sugar-beet harvesters, etc. (digging 20–30 cm into the soil)
• Monoculture-damage management in Gabe Brown-style no-till grain operations

Continuous-cropping damage

• Clubroot (Plasmodiophora brassicae) — soil survival of spores 5–10 years or more
• White rot (Sclerotium cepivorum) — necessity of long rotation for onion
• Bacterial wilt, fusarium wilt, root rot — 3–4 year rotation for processing tomato

Mycorrhizal symbiosis

• See Chapter 5 references (grass / legume symbiosis; Brassicaceae / Chenopodiaceae non-symbiosis)

Masanobu Fukuoka, "tan-no-hyakushō"

• Masanobu Fukuoka, Shizen Nōhō: Wara Ippon no Kakumei (Natural Farming: The One-Straw Revolution) (Shunjusha, 1975)
• Masanobu Fukuoka, Shizen ni Kaeru (Returning to Nature) (Shunjusha, 1983) — the economics of tan-no-hyakushō