These snow crabs are caught in the locals seas and the unique sweet flavor are especially from the female crabs called Kobako-gani. Boiled kani are often served at celebrations in Japan because of their decorative red shells enjoyed at the New Year.
The Zuwai snow crabs are known for their long legs and sweet have different names in Japan depending on where they are caught. For example they are called Matsuba crab when caught in the Sanin region and Echizen crab when caught in Fukui Prefecture. There are the Zuwai crabs from Kanazawa which are a well-known.
The most common way of enjoying zuwai-gani crabs is using a sanbaizu sauce made with shoyu mixed with tsu vinegar and sugar.