Wrist block, wrist bent inwards, middle finger touching thumb. Block with end of forearm (particularly jodan ko uke). Also called koken uke.

Koken-uke (or Ko-uke), Wrist-Joint Block (or Bent-Wrist Block), is a blocking technique. This technique uses the snapping motion of the wrist to deflect an attack. The wrist is bent inwards with the middle finger touching the thumb. The blocking tool is the end of the forearm at the wrist joint.