| Name (Japanese) | Rock oyster (Iwa-gaki / イワガキ / 岩牡蠣) |
| Overall Rating |
Flavor: ★★★★★ Texture: ★★★★☆ Popularity: ★★★★☆ |
| Reference Price |
Value: ★★★★☆ Price range: $15~$25/piece |
| Best Season | Summer (June–August). |
| Did You Know? | Iwa-gaki’s best season is summer; they are large with thick shells. |
| Category | Details |
|---|---|
| 1. Overview |
Official Name: Iwa-gaki (イワガキ) Kanji Name: 岩牡蠣 (Iwa-gaki) English Name: Rock oyster Scientific Name: Crassostrea nippona (main Japanese species) Classification: • Kingdom: Animalia • Phylum: Mollusca • Class: Bivalvia • Order: Ostreida • Family: Ostreidae • Genus: Crassostrea • Species: C. nippona Average Size: Shell length 10–20 cm; weight 300–800 g (can exceed 1 kg) Key Features: Large, meaty, creamy flesh with bold ocean flavor; summer-season oyster |
| 2. Habitat & Distribution |
Found in rocky coastal waters of Japan, especially along the Sea of Japan. Famous production areas include Akita, Ishikawa, and Shimane. Grows naturally attached to rocks rather than being cultivated on rafts. |
| 3. Seasonality |
Best season is summer (June–August). Unlike cultivated Pacific oysters, rock oysters are plumpest in hot months, offering a rare summer delicacy. |
| 4. Sushi Ingredient Profile |
Common Uses: Raw (nama-iwagaki) with citrus, lightly grilled, or served in kaiseki Flavor: Rich, creamy, and deeply oceanic Texture: Firm yet silky, with luxurious mouthfeel Fat Content: Moderate; notable creaminess comes from high glycogen content |
| 5. Preparation & Craftsmanship |
Typically served raw with sudachi or ponzu to balance richness. Requires careful shucking due to large, thick shells. Can be lightly grilled to enhance umami while preserving juiciness. Often featured in high-end sushi and kaiseki restaurants as a seasonal treat. |
| 6. Recommended Pairings |
Sushi Rice: Lightly seasoned to avoid overpowering richness Condiments: Sudachi, ponzu, yuzu zest, or sea salt Drinks: Junmai daiginjo sake, Champagne, crisp white wines (Chablis) |
| 7. Nutritional Information |
High in protein and minerals. Rich source of zinc, iron, and vitamin B12. Contains omega-3 fatty acids and glycogen for energy. |
| 8. Trivia & Cultural Notes |
Known as the “summer oyster” in Japan, contrasting with Pacific oysters (winter season). Considered a luxury delicacy due to large size and limited availability. Valued in regional cuisine along the Sea of Japan coast. Often served with citrus (sudachi or kabosu) to highlight freshness. |
| 9. Recommended Sushi Styles |
• Nama-iwagaki (raw rock oyster) with ponzu or sudachi • Lightly grilled iwa-gaki with citrus glaze • Iwa-gaki nigiri with sea salt • Kaiseki-style oyster with shell presentation • Gunkan-maki using chopped iwa-gaki and scallion |
