Hammer Punch, called Tile Splitter (瓦割り Kawara Wari) in Japan, is a downward-thrusting punch used by Paul Phoenix, Heihachi Mishima and Prototype Jack. It is usually referred to by the translated Japanese name by fans.
it has a guaranteed follow-up on a counter hit, and can be used to stop opponents from tech-rolling and even getting up off the ground in some cases. The command input is d+1.
In Tekken 2, defeating an opponent with a Hammer Punch will send them straight to the ground, irrespective of their position. In the original Tekken, the Hammer/Power Punch combo can be performed in a juggle. Due to a glitch in Tekken 2, a Hammer Punch and its follow-ups can be performed facing the wrong way.
Due to a glitch in Tekken 3, a Hammer/Power Punch juggle combo is also possible in the game, if the opponent is juggled side-on and rotates facing downwards in the air.
An enhanced version of this move is known as the God Hammer Punch, and has been exclusive to Paul Phoenix since Tekken 3. This move can be used to Bound opponents in Tekken 6. Since Tekken 2, Heihachi Mishima has an enhanced, unblockable version of this move called the Lightning Hammer.
The usual input is d+1. Originally, at least with Paul, the player had to already be crouching first.