Previous Position

Same leg position (Kokutsu Dachi) and Crossed Arm Strike with the Left Fist (Ura Zuki)

Feet Position on Diagram Facing Screen

 

Keep the legs in position
Bring the Right forearm back in front of your face until your Right fist is touching your Left shoulder.  At the same time, lower your Left arm down and bring the Left fist under the Right elbow  in an upper-cut motion, striking to the chin area
Breath out partially and tense all your body muscles for a brief moment on the completion of the move
The next move should follow immediately