Start Position

Back Fist Block (Uraken Gamae) in Front Stance (Zenkutsu Dachi)

Breathe in deeply through your nose
Move your Right foot in to your Left, then forward towards the 1.30 clock position so you finish in a wide front stance facing 12 o'clock

As your Right foot starts to move towards your Left, bring your Right fist to your Left shoulder and place your Left fist under your Right elbow - knuckles against your elbow

As you step forward, bring your Right fist forward and down in front of you, finishing with you knuckles facing away from you and directly in line with your chest
Keep your left fist under your Right elbow
Breathe out slowly and strongly through your mouth during the technique, which should last 2 - 3 seconds. 
Tense all your body muscles for a brief moment on the completion of the move