Hand/Arm Board on the Chinese Boxing Synthesis Curriculum picks a dozen of the important striking actions that are needed.  While there are many more than a dozen one can use the ones picked represent the most used angles that are needed in striking.  These angles can have various weapons.  For instance a back hand strike can be with the back of the hand or if rotated 90 degrees can use the side (spade) of the hand or one could use the palm side of the arm to strike from the same angle.  In the Hand Board one also learns about projection and power on many of the techniques shown.  Finally on all of the CB Boards we take the technique shown and then put it into typical uses in the Chinese Boxing Encounter.