A specific type of Inward Parry which is physically distinguishable by the orientation of the hand, fingers pointing forward, in order to effect the block.

Comments:

This maneuver is ideally enacted by an accompanying wrist rotation that expose the heel of the hand and to enhance the inward deflection of the maneuver; thus the inclusion of palm-heel in the name.

This maneuver is employed for lower attacks - usually between the shoulder and hip height.

The word horizontal, in this case, is refers to both the orientation of the hand and the relative plane on which this maneuver travels.