Beef sushi is the unusual specialty of the house here, and you can order it by the piece or in convenient assorted platters. The latter come with different combinations of cooked, raw and lightly seared beef, served both sushi-style and as beef sashimi. Each piece of nigiri-zushi is topped with a morsel of prepared beef, while the gunkan-style sushi is topped with uni or ikura, with a strip of beef taking the place of the seaweed wrapping.
The extensive menu also features beef-tongue dishes, spare ribs, deep-fried jumbo chicken wings, inexpensive steaks, and izakaya-style small dishes like pickles and potato salad. One unusual item is "kushi-tempura" - chunks of beef, beef tongue, avocado or eringi mushrooms that are quick-fried in tempura batter, flavored with shiso and ume paste, and served on thin skewers.
Drinks options include a few decent craft sake (Y680-780 per ichigo serving) as well as budget wines, beer and shochu. Sushi averages around Y200 a piece, so you can just pop in for several pieces and a drink if you're in the mood for bar-hopping, or settle down for a full meal if you're so inclined.
Gyumikura is part of the yokocho drinking alleyway on the ground floor of the Aso Building. The building (Aso-Biru in Japanese) is located at the top of the stairs at the southeast exit of Yokohama Station. If you're coming from the east side of the station, take the passageway on the right-hand side of the post office.