| Name (Japanese) | Red sea urchin (Aka uni / アカウニ / 赤雲丹) |
| Overall Rating |
Flavor: ★★★★★ Texture: ★★★★★ Popularity: ★★★☆☆ |
| Reference Price |
Value: ★★★☆☆ Price range: $35~$60/100g |
| Best Season | Summer to early autumn (July–September) |
| Did You Know? | Known as a “Elusive uni,” its scarcity and delicate nature make it rare. |
| Category | Details |
|---|---|
| 1. Overview |
Official Name: Aka uni (アカウニ) Kanji Name: 赤雲丹 (Aka uni) English Name: Red sea urchin Scientific Name: Heliocidaris crassispina Classification: • Kingdom: Animalia • Phylum: Echinodermata • Class: Echinoidea • Order: Echinoida • Family: Strongylocentrotidae • Genus: Heliocidaris • Species: H. crassispina Average Size: Shell diameter 5–8 cm; roe yield 30–120 g Key Features: Deep golden to reddish roe, rich sweetness, elegant umami; considered a luxury seasonal uni |
| 2. Habitat & Distribution |
Found mainly in warm coastal waters of western Japan. Major production areas include Kyushu, Shikoku, and the Seto Inland Sea. Diet consists of seaweed (kombu, wakame), imparting a refined sweetness. |
| 3. Seasonality |
Best season is summer to early autumn (July–September). Roe develops its richest flavor during peak kelp growth. |
| 4. Sushi Ingredient Profile |
Common Uses: Nigiri, gunkan-maki, uni-don, sashimi Flavor: Sweet, elegant, less briny than bafun uni Texture: Silky yet slightly firmer Fat Content: High; rich umami and creaminess |
| 5. Preparation & Craftsmanship |
Harvested and processed by hand to preserve delicate roe. Served raw to highlight its refined sweetness. Requires precise handling due to rarity and fragile texture. Often presented as luxurious gunkan or premium sashimi. |
| 6. Recommended Pairings |
Sushi Rice: Lightly seasoned, balances richness Condiments: Sea salt, wasabi, or crisp nori Drinks: Junmai daiginjo sake, Champagne, or dry white wine |
| 7. Nutritional Information |
High in protein, vitamins A, E, and B12. Contains omega-3 fatty acids, zinc, and iodine. Rich in amino acids that enhance umami. Nutrient-dense with moderate calories. |
| 8. Trivia & Cultural Notes |
Considered a **rare delicacy** in Japan due to limited production. Known for its luxurious balance of sweetness and elegance. Especially prized in Kyushu and Seto Inland Sea regions. Often commands higher prices than murasaki uni in peak season. |
| 9. Recommended Sushi Styles |
• Uni gunkan (軍艦巻き) with crisp nori • Uni nigiri with sea salt • Uni-don (over sushi rice) as a luxury treat • Uni sashimi highlighting its reddish hue • Paired with ikura for a decadent donburi |
