The form of the fist is the same as in Seiken. However, this time the back of the fist or the knuckles are used.
Uraken is most famous for its variety of angles of attack as well as for its snapping wrist action. It is also possible to use the complete back of the fist instead of just the knuckles. This is often used without the wrist snap. A variation is Yubisaki Uchi, which is a relaxed hand with loose fingertips. This is used to hit the eyes for example.