Many restaurants in Japan focus on one particular ingredient, be it eel, whale or fugu (pufferfish). But few take this single-mindedness to such an extreme as Surugaya Kahei. The specialty at this little counter-type sake bar is shiokara, the salty, odoriferous innards of assorted seafood.

Most izakaya taverns will offer one or more type of shiokara, as a pungent, umami-laden side dish to go with sake. But Surugaya Kahei, run by a Shizuoka fish company, boasts 60 options. Many are variants on the standard squid guts, seasoned with zesty yuzu or spicy kimchi, for example. Others include katsuo (skipjack tuna), scallop, zuwaigani (snow crab) or pricy sakuradai (sea bream).

Order a taste-and-compare set of three or five kinds. The flavors range from mellow to wickedly intense. Part of the fun is finding the right drink to pair with them. The sake selection changes, but a couple of names to look out for are Kikuyoi (a Shizuoka favorite) and Tamagawa (from Kyoto).

Most people find a little shiokara goes a long way. Mercifully, there is also a more mainstream menu of izakaya foods — from fresh oysters and sashimi to sushi and seafood donburi rice bowls.

Look for Surugaya Kahei in the refurbished redbrick former Manseibashi railway station, equidistant between Ochanomizu, Akihabara and Kanda.