Ooinoue Yasushi 大井上康

Ooinoue Yasushi 大井上康 (1892–1952)

Born: August 21, 1892, Etajima Naval Academy, Hiroshima Prefecture
Died: September 23, 1952, age 60
Known for: The Nutritive Cycle Theory (栄養週期理論) and breeding the Kyoho grape (巨峰)

Ooinoue is Cho Han-Kyu's second teacher (after God) in Cho's own hierarchy of influences. His nutritive cycle theory is the intellectual foundation upon which KNF's entire approach to plant nutrition is built.

Life

Son of a naval officer, Ooinoue suffered tuberculosis-related arthritis as a child, leaving one leg disabled. This steered him from a military career toward agricultural science. He graduated from Tokyo Agricultural University in 1914 and began work at a grape garden in Ibaraki Prefecture.

In 1919, he established his own research institute in Shizuoka Prefecture, overlooking Mount Fuji. In 1922 he traveled to France, Germany, and England to study horticultural techniques. By 1930 he had published a 900-page monograph on grapes and became the first Japanese person elected to the French Academy of Agricultural Sciences.

In 1936, he published his revolutionary Nutritive Cycle Theory. In 1937, he began the grape cross that would produce the Kyoho variety. During World War II, the military classified fruit trees as "non-essential and frivolous crops" and confiscated his research grapes.

His theory was "regarded as heretical" (異端視される) by the agricultural establishment. He left the academic community and became a private researcher. He died in 1952, unrecognized. Five years after his death, the Ministry of Agriculture rejected the Kyoho grape's seed registration.

The Nutritive Cycle Theory (栄養週期理論)

The core principle: plants need different nutrients at different stages of growth. Rather than applying large amounts of fertilizer at planting (standard practice), Ooinoue proposed timed, sequential application:

Seedling/Sprouting: Withhold all nutrients, especially nitrogen. Let roots establish.
Vegetative growth: Apply nitrogen only after roots have anchored.
Flower bud formation: Cut nitrogen entirely. Apply phosphorus and potassium.
Fruit maturation: Cut P and K. Apply calcium.
Ripening: Strategic trace elements only.

The fundamental insight: the farmer must manage the plant's internal nutritive state across its life cycle, actively guiding the transition from vegetative growth (栄養生長) to reproductive growth (生殖生長). This is what Ooinoue called "nutritive cycle cultivation."

The C/N Ratio Framework

Building on the work of American researchers Kraus and Kraybill (1918), Ooinoue identified four plant nutritive conditions based on the carbon-to-nitrogen ratio in plant tissue:

Type 1 (High N, Low C): Weak growth, no flowering — overfed with nitrogen
Type 2 (Med-High N, Low-Med C): Vigorous leaves but no viable fruit — "running to vine"
Type 3 (Medium N, Med-High C): Strong flowering, quality fruit — OPTIMAL
Type 4 (Low N, High C): Stunted — starved of nitrogen

Ooinoue's critical addition beyond Kraus-Kraybill: the C/N ratio changes dynamically across the plant's life cycle, and the farmer must actively manage these transitions through timed fertilization. This is the "cycle" in "nutritive cycle."

Modern Scientific Validation

Ooinoue's core insight has been substantially validated by modern molecular biology, though without direct reference to his work. Key studies have confirmed:

The C/N ratio in phloem sap increases during floral transition (Corbesier et al., 2002)
Withholding nitrogen promotes flowering through the FBH4/FT molecular pathway (PNAS, 2021)
Carbon and nitrogen signaling regulate flowering time through the FLC gene (PMC, 2024)
N, P, and K each have distinct effects on flowering timing through specific signaling pathways (Journal of Experimental Botany, 2025)

None of these modern papers reference Ooinoue by name. His contribution — applying the C/N ratio insight to practical agriculture through timed fertilization — remains unrecognized in Western scientific literature.

The Kyoho Grape (巨峰)

Ooinoue crossed Ishihara Wase (V. labruscana) with Centennial (V. vinifera) beginning in 1937. The cross was completed in 1942, and he named the new variety "Kyoho" (巨峰, "great peak") in 1946, after Mount Fuji visible from his research institute.

Despite the Ministry of Agriculture's rejection of its seed registration in 1957, Kyoho became Japan's dominant grape variety. Today:

~60% of grapes shipped in Japan are Kyoho or Kyoho-derived varieties
Improved descendants include Pione and Fujimimori
As of 2015, the most cultivated grape variety in the world by land area (365,000 hectares, >90% in China)

Connection to Korean Natural Farming

Cho arrived in Japan in 1965 to study under Ooinoue. The man had been dead for 13 years. Cho went to his study and read every book he had left behind — especially Shin Saibai Gijutsu no Riron Taikei (Theoretical System of New Cultivation Technology), which he read "more than a dozen times."

"The straightforward logic on the physiological and behavioral pattern of plants gave me wisdom to treat the plants with a new perspective, and his theory of the Nutritive Cycle has enabled me to talk with the plants."

Cho's radical adaptation was to replace every chemical input with a biological equivalent while preserving the timing framework:

Seedling stage: Instead of withholding nutrients → inoculate with microbes (IMO + LAB + BRV)
Vegetative growth: Instead of chemical nitrogen → FAA (Fish Amino Acid)
Changeover/flowering: Instead of phosphoric acid → WCP (Water-soluble Calcium Phosphate from bone)
Fruit maturation: Instead of chemical calcium → WCA (Water-soluble Calcium from eggshells)
Ripening: Instead of chemical trace elements → Sea Water

Cho also added inputs that Ooinoue's framework never included: FPJ (Fermented Plant Juice) as baseline nutrition, OHN (Oriental Herbal Nutrient) as plant medicine, LAB (Lactic Acid Bacteria) for soil conditioning, and the "changeover treatment" using WCP to trigger the vegetative-to-reproductive transition in perennial fruit trees.

Legacy

Ooinoue's former research institute in Izu City, Shizuoka Prefecture is a nationally registered tangible cultural property. The Japan Kyoho Society preserves his legacy and keeps his books in print. The Nutritive Cycle Theory Study Group published a 2022 Kindle transcription of his 1950 public lecture.

A bronze statue commemorates him, and his original 1948 book — the one Cho read more than a dozen times — is available in a revised 2011 edition through the Japan Kyoho Society.

Sources

大井上康 — Japanese Wikipedia
JATAFF: "たしかな事実のあかし — 巨峰を創った大井上康と仲間たち"
FoodWatch Japan editorial, 2013
Japan Kyoho Society (kyoho-kai.net)
National Diet Library catalog and digital archives
Cho Han-Kyu, Janong Natural Farming (2004)
Cho Han-Kyu lecture transcripts, 2017–2018 (PKNF archive)
Kraus & Kraybill, "Vegetation and Reproduction with Special Reference to the Tomato" (1918)
Corbesier et al., Plant and Cell Physiology 43(6), 2002