Why source from Japan
Sea of Japan coast wild-harvest produces iwagaki distinct from cultivated magaki in size and seasonality; specialty summer fine-dining ingredient.
Key spec
Shell 10-15 cm; protein 8-10%; zinc 5-15 mg/100g; glutamate-rich umami profile.
Typical end-product
Fine-dining summer sashimi, hospitality export, gift-economy retail.
At a glance
- Suppliers listed
- 1 supplier
- Typical MOQ
- 10–100 kg live; 5–25 kg shucked frozen
- Typical lead time
- 4–8 weeks (in season)
- Regions of origin
- Yamagata, Akita, Niigata, Hyogo (Sea of Japan coast)
- Category
- Food ingredients
- Harvest season
- June – August (summer wild-harvest)
- Japan regulatory status
- Food product; phytosanitary for live; shellfish-allergen
- Japanese name
- 岩牡蠣
- Romaji
- 岩牡蠣
About this ingredient
Wild-harvest Japanese rock oyster (Crassostrea nippona) — the larger, summer-harvested counterpart to the cultivated 'magaki' (Pacific oyster, Crassostrea gigas). Distinguished by larger size (often 10-15 cm shell), creamier texture, and summer harvest (June – August) vs magaki winter harvest. Yamagata, Akita, and Niigata along the Sea of Japan coast host the principal commercial wild-harvest. Specialty fine-dining and gift-economy retail. Distinct from existing scallop / abalone / fugu / kuruma-prawn shellfish entries.
Regulatory status
| Japan | Food product; phytosanitary for live; shellfish-allergen |
|---|---|
| EU | Food import; shellfish-allergen labelling |
| United States | GRAS; FDA Prior Notice; shellfish-allergen labelling |
| China | GACC; live-shellfish inspection |
Looking for alternatives?
Common reasons buyers swap to a different ingredient — and what we'd suggest based on this ingredient's profile.
Vegan / plant-based alternatives
Iwagaki (Japanese Rock Oyster) is animal-derived. If you need a non-animal source with similar functions, consider:
Sansho Pepper
山椒
Zanthoxylum piperitum source; INCI Zanthoxylum Piperitum Fruit Extract; MOQ from 1–10 kg (dried peppercorn); 100 g – 5 kg (powder).
Plant-based· shares 3 categories
Wasabi Powder
山葵粉末
Wasabia japonica (Eutrema japonicum) source; INCI Wasabia Japonica Root Powder; MOQ from 1–10 kg (powder); 100 kg+ (bulk paste).
Plant-based· shares 3 categories
Shio Koji
塩麹
MOQ from 20–100 kg.
Plant-based· shares 3 categories
When does it make sense to swap an ingredient? Read the swap guide →
Japanese suppliers
Disclaimer
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Last updated: 2026-05-05