In Japan it is usually cooked in a hotpot and eaten with a group of friends as kani-nabe or kani-suki, with boiled or steamed vegetables. As kani-zu, the shellfish is boiled and eaten with a vinegar dipping sauce, such as ginger vinegar or ponzu. When the flesh from below the claws is dipped into hot soup, or boiling water as in kani-shabu, this is referred to as hanasaki-gani – the ‘flower opening’ crab, from the way the meat slowly expands and opens.
Kani is also good steamed, especially in a traditional wooden mushiki crab steamer, as pictured (bottom) here, at Beniya Mukayu, a deluxe ryokan inn in Kaga, Ishikawa Prefecture. Incidentally, Beniya Mukayu's seafood-based cuisine (pictured above) is top class.
Just to confuse matters, Hanasaki-gani is also a variety of King Crab, a spiky-haired shellfish specimen found off of Nemuro, in Hokkaido. There are many regional varieties, including ke-gani horsehair crab, commonly nicknamed okuri-gani literally, ‘giant chestnut crab’, which is famous in Hokkaido, and the watari-gani blue crab, the same species often found in markets across Asia. Koppegani, the female snow crab (pictured here below) is famed for its tasty roe.
One of the tastiest is the zuwai-gani snow crab which is taken on the Japan Sea coast, especially off Fukui and Ishikawa Prefectures. It is also called the Echizen-gani after the Echizen coastline. In Kansai it is called matsuba-gani, the ‘pine-leaf’ crab. It is exquisite when steamed very fresh, and dipped in ponzu. Tottori’s matsuba-gani cuisine and Fukui’s Echizen-gani cuisine are famed, and day-trip gourmet bus tours run from Osaka and Kyoto to the coast during the season.
Kani aficionados go for the legs and claws, and the kanimiso tucked away beneath the kora carapace. Once you've extracted all the flesh, you can can fill the kora with hot sake, and slurp up the warm, sea-salty brew. You can eat crab in the privacy of your own home, of course, but as it's a time-consuming, and frankly messy business, cracking crab claws and scooping crabmeat from the legs, most people go to a kani-ryori specialist. The chefs, and waiters and waitresses, do the hard work for you.
Freshwater crab are found in pure waters throughout the archipelago. Most common are sawa-gani, which are often deep-fried – still wriggling – as kara-age. It’s long armed cousin, the Nihon tenaga-ebi, is found especially in Kochi where it is served as part of a formal meal, or just as it is, salted and deep-fried, accompanied with, oh yes, cold beer or nihonshu.