The basic shape is the "Rikyū shape" (Rikyū-gata), which are a large "natsume" canister, a medium "natsume" canister, and a small "natsume" canister, but there are many other variations, too.
また形は利休型とされる大棗・中棗・小棗が基本形となっているが、多くのバリエーションを持つ。