A hammerblow is a martial arts attack made with both hands interlocked at the fingers. The added weight and control (as opposed to a regular punch) allows for a slower, but more powerful strike.

To execute, one brings their palms together (slightly off-centre), locks the fingers downward, then swings at an opponent as if they were holding a club-weapon (like a bat). When performed properly, the strong muscle on the side of the hands can cause a great deal of damage especially against bony protrusions on the face. When grappling, the hammerblow can be performed directly upwards (like an uppercut) and will likely shatter the chin.