Kumagai Sushi serves an omakase sushi course in the basement of a building in the Akasaka office district, near Tameike-sanno Station. The course centers on seasonal fish, alternating nigiri with cooked dishes and including sushi finished with smoking or curing. Lunch visits are booked in advance and repeat, with each course served in sequence alongside explanations of the seasonal ingredients. The room is quiet and the meal proceeds slowly.