The striking technique with the back of the hand uses the power from the snapping motion of the elbow and can be performed in two different forms: horizontal and vertical.
Uraken uchi occurs very often in the kata. In combination with Yoko geri keage, the technique is repeatedly used in the kata as a defensive technique (Uraken uke). This combination occurs for the first time in Heian nidan.

Here you will find all information about the techniques in the video