1. Set back on one leg, drawing the rear arm across to the opposite knee, placing the back of the hand on the thigh. Draw the lead hand back to the hip. Step forward into mabu feeling stance and do a high block and single tazhang. Keep under the extending arm so that the tazhang comes from a protected place. Tuck the striking hand up towards the jaw as it starts to move forward, so that it extends high. As it reaches almost full extension, drop it down to chest height.
2. You may also turn to a full mabu with a quite extended upper block.
(the final position looks very much like a zhuangzhang tiaoda, but the line of action is different so the direction of the strike is downward)