Food · Fermented foods
Nagaimo (Chinese Yam / Japanese Long Yam)
ながいも (Nagaimo)
Also known as: Nagaimo, Chinese yam, Japanese long yam, Dioscorea polystachya, Dioscorea opposita, 長芋, Yamatoimo (Yamato yam, distinct cultivar), Ichoimo (ginkgo yam, distinct cultivar)
Looking for a Japanese supplier of Nagaimo (Chinese Yam / Japanese Long Yam)? Tell usAt a glance
| Category | Food |
|---|---|
| Japanese labeling name | ながいも |
| Common Japanese notations | ながいも, 長芋, ナガイモ, 山芋, 大和芋 (yamatoimo, distinct cultivar), いちょう芋 (ichoimo, distinct cultivar) |
| Origin | Long yam / Chinese yam (Dioscorea polystachya, formerly D. opposita); the volume cultivated yam in Japan; principal modern production regions Aomori (the volume leader at ~40-50% of domestic supply, particularly Towada area), Hokkaido, Nagasaki, Chiba; multiple cultivars including straight nagaimo, yamatoimo (Yamato yam, fan-shaped), and ichoimo (ginkgo-leaf-shaped) |
| Typical functions | Tororo (grated yam) — the volume retail and foodservice category, Fresh slicing (yamaimo no tanzaku, raw shredded yam in Japanese izakaya cuisine), Okonomiyaki binder ingredient (volume processed-food application), Yamatoimo as Japanese confectionery (joyo manju, kanten yokan binder), Industrial freeze-dried yamaimo powder (food ingredient), Premium gift retail (Aomori brand, regional varieties) |
| Regulatory status in Japan | Nagaimo follows standard agricultural product labeling. Cultivar disclosure (nagaimo / yamatoimo / ichoimo) is significant for premium positioning. Origin disclosure (Aomori volume leader, Hokkaido, Nagasaki) is essential. Yam (yamaimo) is a JAS-recommended-disclosure allergen — oral allergy syndrome reactions are documented and disclosure is standard practice for processed products. |
Nagaimo (ながいも) — long yam (Dioscorea polystachya, formerly D. opposita) — is the volume cultivated yam in Japan and the foundation of the mass-market tororo (grated yam) retail and foodservice category. While jinenjo (Japanese wild yam) commands ultra-premium positioning, nagaimo is the practical volume choice for most yam OEM applications. Aomori Prefecture dominates domestic production (approximately 40-50% of supply, particularly the Towada area), with Hokkaido, Nagasaki, and Chiba as major secondary regions. The OEM applications are diverse and substantial: as the foundation of fresh and frozen tororo retail, as a fresh raw ingredient for yamaimo-no-tanzaku and izakaya foodservice, as a binder ingredient for okonomiyaki and other processed foods (volume application), as the basis of yamatoimo (fan-shaped cultivar) for traditional Japanese confectionery (joyo manju, kanten yokan), and as freeze-dried yamaimo powder for industrial food ingredient supply. Three principal cultivar groups exist: standard nagaimo (cylindrical 30-50cm × 5-7cm), yamatoimo (大和芋, fan/fist-shaped, intermediate viscosity, traditional confectionery use), and ichoimo (いちょう芋, ginkgo-leaf-shaped, premium kaiseki use).
Find OEM manufacturers
Browse Japanese OEM manufacturers that build products in this category. Filter by small lot, certifications, prefecture.
Classification
Tags below link to other ingredients sharing the same attribute, so you can pivot from one ingredient to its peers.
Product applications
Functions
Regulatory tags
Origin
Common OEM product categories
Finished-product categories where Japanese OEM manufacturers commonly formulate with this ingredient.
- Fresh whole nagaimo retail (volume retail, with origin disclosure — Aomori, Hokkaido, Nagasaki)
- Cut and vacuum-packed nagaimo (convenience retail format)
- Frozen tororo / grated yam (major convenience format)
- Yamatoimo (fan-shaped cultivar) for traditional confectionery
- Ichoimo (ginkgo-leaf-shaped cultivar) for premium foodservice
- Freeze-dried yamaimo powder (industrial ingredient)
- Tororo-soba ready-meal retail (using nagaimo)
Ingredient profile
Nagaimo is Dioscorea polystachya (formerly classified as D. opposita), Chinese yam or Japanese long yam, originating from China and well-established in Japan since ancient times. Modern domestic production has developed sophisticated cultivar diversity for different positioning categories.
Major cultivars: (1) Standard nagaimo — cylindrical, 30-50cm × 5-7cm, the volume cultivar. Aomori Towada area is the dominant production region. Lower viscosity than jinenjo, milder flavor, suitable for volume tororo retail. (2) Yamatoimo (大和芋) — the Yamato area cultivar, fan-shaped or fist-shaped, intermediate viscosity, distinctly suited to traditional Japanese confectionery use (joyo manju binder, kanten yokan structure). Traditional Yamato region (Nara Prefecture) is the historical origin, with modern production also in other regions. (3) Ichoimo (いちょう芋) — ginkgo-leaf-shaped, a regional Saitama and Gunma cultivar, premium kaiseki and gift retail positioning.
Nutritionally, raw nagaimo per 100g provides 64 kcal, 2.2g protein, 0.3g fat, 13.9g carbohydrates with 1.0g dietary fiber. Mineral content includes K 430mg, Mg 17mg, P 27mg per 100g. Yamatoimo is more nutrient-dense (higher protein, more minerals) than nagaimo.
Industrial supply: Aomori at ~40-50% domestic share is the volume leader (Towada area is the established production heartland). Hokkaido, Nagasaki (Shimabara peninsula), and Chiba follow. Total domestic production exceeds 150,000 tonnes annually. Significant export volume to Taiwan and other markets exists, with Japan-origin premium positioning.
OEM applications
Tororo (grated yam) — the volume retail and foodservice category. Fresh whole nagaimo for home grating, frozen tororo retail packs (convenience format with growing share), and tororo-soba and tororo-meshi foodservice are all major applications. Lower viscosity than jinenjo but adequate for mainstream tororo positioning at substantially lower cost.
Yamaimo-no-tanzaku and izakaya raw applications — fresh nagaimo cut into thin julienne strips, served raw with soy sauce, wasabi, or ume sauce. Established izakaya foodservice signature.
Okonomiyaki binder — grated nagaimo or yamatoimo is added to okonomiyaki batter to provide structure and lightness. Okonomiyaki is a major Japanese cuisine category and this is a substantial volume application.
Traditional Japanese confectionery — yamatoimo (fan-shaped cultivar specifically) is essential for joyo manju (a premium Japanese steamed bun), kanten yokan structure, and other traditional Japanese pastries (wagashi). The cultivar produces unique gel-forming and binding properties when grated.
Industrial freeze-dried yamaimo powder — produced for food ingredient supply, used in noodles (some yamaimo-soba and yamaimo-udon SKUs), confectionery, and processed-food applications.
Premium gift retail — Aomori Towada nagaimo, Saitama ichoimo, and traditional Yamato yamatoimo are established premium gift categories.
For OEM: volume fresh nagaimo retail packs (Aomori-origin verifiable for premium positioning), frozen tororo retail OEM (major growth category), yamatoimo for traditional confectionery binder supply, ichoimo for premium foodservice and gift retail, freeze-dried yamaimo powder ingredient supply, and tororo-soba ready-meal retail OEM.
Regulatory classification in Japan
Standard agricultural product labeling. Cultivar disclosure (nagaimo vs yamatoimo vs ichoimo) is essential for premium positioning.
Origin region disclosure: Aomori (Towada area), Hokkaido, Nagasaki, Chiba, Yamato area (Nara) for yamatoimo, Saitama/Gunma for ichoimo.
Yamaimo allergen disclosure: yamaimo (jinenjo, nagaimo, yamatoimo, ichoimo collectively) is a JAS-recommended-disclosure allergen. Standard practice is to disclose yamaimo content in processed products.
Aomori Towada nagaimo regional brand: established consumer recognition though not formally GI-registered.
Regulatory classification in other markets
| EU | Imported as Chinese yam or Japanese yam. No mandatory allergen disclosure but yam recognized as oral allergy syndrome trigger. Established export market for nagaimo. |
|---|---|
| USA | Imported under FDA standard food procedures. Established in Japanese-cuisine specialty channels. Frozen tororo and freeze-dried yamaimo are export-friendly formats. |
| China | Imported under GACC rules. China is itself a major Chinese yam producer. Japanese-origin Aomori nagaimo positioned as premium specialty. |
| Korea | Imported as Japanese specialty. Korea has its own ma (마, yam) culture. Japanese-origin nagaimo and yamatoimo positioned as specialty imports. |
Market reference formulations
Example finished products will be added after verification of cultivar (nagaimo / yamatoimo / ichoimo), origin (Aomori / Hokkaido / Nagasaki / other), and target product format.
All brand names and product names referenced anywhere on this site are the property of their respective owners. Example entries are provided for informational purposes only and do not imply endorsement.
Seasonality & supply calendar
- Harvest months
- Autumn-harvested: November – December; spring-harvested: March – April
- Peak supply
- November – December and March – April
- Off-season
- Stored 長芋 supplies through summer
Source: 農林水産省 野菜生産出荷統計. Aomori and Hokkaido lead production.
Storage requirements
How the receiving OEM facility needs to handle inbound raw material.
- Temperature
- Storage 0–4°C wrapped
- Conditions
- Whole tubers store longer; cut surfaces oxidize quickly
- Shelf life
- Whole 1 month chilled; cut 5 days
Supply concentration
Where this ingredient comes from — useful for single-source-risk planning.
- Primary regions
- Aomori (approximately 37–40% national share per 野菜生産出荷統計), Hokkaido, Nagano
- Import dependence
- 100% domestic
農林水産省 野菜生産出荷統計
Certifications commonly available
Certification schemes commonly obtainable for this raw material. Always confirm the specific supplier's current certificate before contracting.
| Scheme | Availability | |
|---|---|---|
| Organic JAS | On-request | |
| Halal | Inherent | |
| Vegan | Inherent |
Alternative ingredients
Related ingredients commonly evaluated as substitutes.
Quick answers
- What is Nagaimo (Chinese Yam / Japanese Long Yam)?
- Nagaimo (ながいも) — long yam (Dioscorea polystachya, formerly D. opposita) — is the volume cultivated yam in Japan and the foundation of the mass-market tororo (grated yam) retail and foodservice category. While jinenjo (Japanese wild yam) commands ultra-premium positioning, nagaimo is the practical volume choice for most yam OEM applications. Aomori Prefecture dominates domestic production (approximately 40-50% of supply, particularly the Towada area), with Hokkaido, Nagasaki, and Chiba as major secondary regions. The OEM applications are diverse and substantial: as the foundation of fresh and frozen tororo retail, as a fresh raw ingredient for yamaimo-no-tanzaku and izakaya foodservice, as a binder ingredient for okonomiyaki and other processed foods (volume application), as the basis of yamatoimo (fan-shaped cultivar) for traditional Japanese confectionery (joyo manju, kanten yokan), and as freeze-dried yamaimo powder for industrial food ingredient supply. Three principal cultivar groups exist: standard nagaimo (cylindrical 30-50cm × 5-7cm), yamatoimo (大和芋, fan/fist-shaped, intermediate viscosity, traditional confectionery use), and ichoimo (いちょう芋, ginkgo-leaf-shaped, premium kaiseki use).
- What is the regulatory status of Nagaimo (Chinese Yam / Japanese Long Yam) in Japan?
- Nagaimo follows standard agricultural product labeling. Cultivar disclosure (nagaimo / yamatoimo / ichoimo) is significant for premium positioning. Origin disclosure (Aomori volume leader, Hokkaido, Nagasaki) is essential. Yam (yamaimo) is a JAS-recommended-disclosure allergen — oral allergy syndrome reactions are documented and disclosure is standard practice for processed products.
- What products typically use Nagaimo (Chinese Yam / Japanese Long Yam)?
- Fresh whole nagaimo retail (volume retail, with origin disclosure — Aomori, Hokkaido, Nagasaki) / Cut and vacuum-packed nagaimo (convenience retail format) / Frozen tororo / grated yam (major convenience format) / Yamatoimo (fan-shaped cultivar) for traditional confectionery / Ichoimo (ginkgo-leaf-shaped cultivar) for premium foodservice / Freeze-dried yamaimo powder (industrial ingredient) / Tororo-soba ready-meal retail (using nagaimo)
- Where does Nagaimo (Chinese Yam / Japanese Long Yam) come from?
- Long yam / Chinese yam (Dioscorea polystachya, formerly D. opposita); the volume cultivated yam in Japan; principal modern production regions Aomori (the volume leader at ~40-50% of domestic supply, particularly Towada area), Hokkaido, Nagasaki, Chiba; multiple cultivars including straight nagaimo, yamatoimo (Yamato yam, fan-shaped), and ichoimo (ginkgo-leaf-shaped)
- What is the INCI / JSCI labeling name for Nagaimo (Chinese Yam / Japanese Long Yam)?
- JSCI: ながいも
Related ingredients — substitutes, pairings, processing chain
Often used with
Ingredients frequently paired in the same recipe or formulation.
Same category
Other ingredients in the same sub-category.
Explore related ingredients
Used in similar product applications
Other ingredients commonly used in the same finished-product families.
Abura-age (Fried Thin Tofu)
油揚げ
Seasonings & saucesFermented foods
Agemaki (Jackknife Clam)
あげまき
Seasonings & saucesFermented foods
Ago Dashi (Flying Fish Stock)
あごだし
Seasonings & saucesFermented foods
Ahiru-niku (Domestic Duck)
あひる 肉
Seasonings & saucesFermented foods
Aigamo-niku (Hybrid Duck)
かも あいがも 肉
Seasonings & saucesFermented foods
Sharing similar functions
Ingredients that overlap on functional benefit tags.
From the same origin
Other ingredients that share an origin classification.
Related guides & how-to
Related case studies
Regulatory guidance
Take the next step
FAQ for OEM buyers
Q. What's the difference between nagaimo, yamatoimo, and ichoimo for OEM positioning?
All three are cultivars of Dioscorea polystachya but with distinct characteristics and positioning: (1) Standard nagaimo — cylindrical, 30-50cm × 5-7cm, the volume cultivar (Aomori Towada is the production heartland). Lower viscosity, milder flavor, broad applications. Best for volume fresh retail, frozen tororo, izakaya yamaimo-no-tanzaku, and as a general processed-food binder. (2) Yamatoimo (大和芋) — fan-shaped or fist-shaped, originally Yamato area (Nara Prefecture) cultivar, with distinctly higher protein and intermediate viscosity. Traditional and indispensable for joyo manju (Japanese steamed bun), kanten yokan structure, and other traditional wagashi confectionery. The unique binding and gel-forming properties when grated are essential for these applications. Yamatoimo is also used in premium tororo. (3) Ichoimo (いちょう芋) — ginkgo-leaf shape (the name 'ginkgo yam' refers to the leaf-like shape of the tuber), Saitama and Gunma regional cultivar, premium kaiseki and gift retail positioning. The shape allows distinctive presentation in formal cuisine. For OEM positioning: standard nagaimo for volume retail and processed-food applications; yamatoimo specifically for traditional Japanese confectionery (joyo manju, etc.) — substituting standard nagaimo will not produce equivalent results; ichoimo for premium kaiseki and regional gift retail.
Sources · Last reviewed: 2026-04-28
- Editorial — Japan nagaimo cultivar positioning reference
- 農林水産省 (Ministry of Agriculture, Forestry and Fisheries) cultivar registration database
Search the academic literature
Pre-filled queries for the major research databases. Opens in a new tab.
Official regulatory databases
External links to public Japanese / international regulatory authorities. We are not affiliated.
References
- 文部科学省 (Ministry of Education, Culture, Sports, Science and Technology) Standard Tables of Food Composition — ながいも 各形態
- Aomori Towada nagaimo production region reference
- Editorial — Japan yam cultivar landscape reference
Last updated: 2026-04-28. Ingredient entries are reviewed at least annually against current regulatory listings.