Northern sea urchin nigiri

Northern sea urchin (Kitamurasaki uni)

【Nigiri sushi: Gyoran】
What is Kitamurasaki uni?
Kitamurasaki uni (Northern sea urchin) is distributed a little more south than Ezobafun uni and on occasion in Sagami Bay. On the Pacific side of Japan, this species inhabits the area from the Sanriku region to Hokkaido. On the Sea of Japan side, they are distributed across nearly all areas. The main production area is between Hokkaido and Toyama. Their shell is about 10 cm in diameter and larger than that of the Ezobafun uni, which lives in similar areas. Their spines are long and feel a little sparse compared to the Ezobafun uni. A thin line runs vertically along the surface of its shell. It is usually a dark purple color, but some can be slightly brownish. The spawning season is from September to January.

Kitamurasakiuni is not found east of Cape Erimo, including Tokachi, Kushiro, Nemuro, and Rausu on the right side of Shiretoko. It is caught in the vicinity of Hakodate, which faces the Tsugaru Strait and Funka Bay, Minamikayabe (famous for Makombu), and the Hidaka region (famous for Hidakakombu) on the Pacific side up to Cape Erimo.

What does Kitamurasaki uni (Northern sea urchin) nigiri sushi taste like?
Although the Northern sea urchin (Kitamurasaki uni, Strongylocentrotus intermedius) is often mistaken for a member of the Murasaki uni group based on its name, taxonomically it belongs to a different group. Rather, it is closely related to bafun uni and ezobafun uni—which are known for their rich sweetness—and is classified in the same family, Oobafununiidae.

As a sushi topping, Kitamurasaki uni has a firm texture yet melts smoothly on the tongue. It is characterized by moderate sweetness and a rich, briny aroma that spreads across the palate, leaving a pleasant aftertaste. Compared to ezobafun uni, Kitamurasaki uni is generally considered to have a more delicate flavor, offering a distinct appeal that differs from the richness of ezobafun uni.

While sea urchin is generally served as gunkan-maki, some restaurants place individual sea urchin grains directly on top of the sushi rice, based on the belief that the flavor of the sea urchin might otherwise be overshadowed by the nori. This technique allows Kitamurasaki uni to slowly melt on the warm rice, releasing its aroma—a touch that reflects the sushi chef’s dedication to preserving the natural fragrance of the sea urchin.

Additionally, when an omakase course includes a strong-flavored topping such as otoro, chefs may choose Kitamurasaki uni, with its more subtle flavor, to create a better balance throughout the course.

Incidentally, the “Kita” in “Kitamurasaki uni” comes from the fact that it is widely found in the northern waters of Japan. The name “Murasaki uni” (Purple Sea Urchin) comes from the purple hue of its shell.

Also called Naked sea urchin.

【Temperature of vinegared rice (shari) and sushi toppings】
34～36℃/15～18℃

【Main area/season】
Okushiri Island: June to early August
Esashi, Kaminokuni, Setana: Mid-June to early August
Rishiri, Rebun Island: June to early September
Teuri, Yakijiri Island: Late June to early September
Shakotan, Otaru: Early June to late August
Funka Bay (Toyoura, Lake Toya, etc.): June to August
Hakodate vicinity (Toi, Shiriuchi, Matsumae, etc.): Winter and spring
From the Sanriku region to the Shimokita Peninsula: Summer

【Trivia】
At Mutsu city, in Aomori prefecture, they are working on the testing project of farming Kitamurasaki uni (Northern sea urchins), feeding them various cabbages (standard Cannonball Cabbage and Chinese napa cabbage and etc). Those vegetables are recycled food wastes from supermarkets. The idea is that during the winter season, the natural sea urchin becomes rare and there is barely one on the market, therefore they get those farmed sea urchins on the market instead and aim to generate a new source of income. The farmed sea urchin gets as ripe as the natural one, and those ingredients that create the acquired sea urchin flavor such as Glycine, Methionine and Amino acids are well contained.

【Famouos Manufacturers】
The four major brands of Toyosu Market "Hadate, Higashizawa, Tachibana, and Murakami" have factories in the vicinity of Hakodate. Ogawa Shouten, which produces Ezobafununi and Kitamurasakiuni, has a factory in Toyako Town on the north side of Funka Bay. Hokkaido Ichikawa, which specializes in Rishiri sea urchin, is located in Chitose City, which has an airport.

【Related contents】
Global sea urchin resources

What is uni sushi?

Why is it that sea urchin sushi can taste bitter?

Nori (Dried laver seaweed)

List of Nimono, Gyoran and Others

(Revision date: June 25, 2026)