Jinenjo (Japanese Wild Mountain Yam)

The three yams are distinct species and distinct positioning categories: (1) Jinenjo (Dioscorea japonica) — Japanese wild yam, native to Japan, thin elongated shape (60-100cm × 2-4cm), the highest viscosity when grated, deepest umami, and most premium pricing (3-5× nagaimo, 10× for wild-foraged). Used for premium tororo and traditional Japanese cuisine. Hard to industrially scale — small total volume. (2) Nagaimo (Dioscorea polystachya / D. opposita — long yam) — the volume cultivated yam in Japan, originating from China but well-established in Japan. Cylindrical 30-50cm × 5-7cm, lower viscosity than jinenjo, milder flavor. The major retail and foodservice yam category by volume (Aomori, Hokkaido, Nagasaki are major production regions). Most 'tororo' in volume retail and foodservice uses nagaimo. (3) Yamatoimo (大和芋, Dioscorea polystachya cultivar) — Yamato area cultivar with distinctive fan or fist shape, intermediate viscosity, traditional in kaiseki and Japanese confectionery (notably as binder for Japanese pastries — joyo manju, kanten yokan, etc.). For OEM positioning: jinenjo for ultra-premium specialty applications and gift retail; nagaimo for volume tororo retail, foodservice, and processed food applications; yamatoimo for traditional confectionery binding and specialty kaiseki applications. Cultivar/species disclosure is essential for premium positioning — labeling 'jinenjo' on a nagaimo product would be a serious consumer protection violation.