Yotsuya 3-11, Dai-ni Komyodo Bldg B1F. Open 5-9:30pm (LO; Sat 3-8pm). Closed Sundays.
Oysters and himono (grilled dried fish) are the specialty here, along with a huge selection of sake. The sake is served in small portions for Y300-400, so you can try a number of different types.