Sushi Umi Jamsil is a sushi restaurant serving omakase in the Sofitel at Jamsil, near Seokchon Lake. It pairs aged fish with red vinegar shari blended without sugar, and the course includes tsukami and truffle chawanmushi. Reservations are required, and on weekday dinners guests enter on the hour after booking through an app. The base seasoning of the shari is on the strong side, which is a drawback.