East Shinjuku is really two a daytime quarter of department stores, vertical malls, and discount stores, and a nighttime quarter of bars (straight and gay), cheap restaurants, strip joints, game parlors, jazz clubs, rooms-by-the-hour hotels, raves, and honky-tonks most of the latter in a seedy, neon-lit neighborhood called Kabuki-cho.
By day East Shinjuku is known for its shopping, by night it's known for its bars and strip clubs.