Horizontal Misalignment of the Hammer Die

This occurs when the hammer die (typically the obverse die) shifts laterally to the anvil die. The die may shift within its recess when the bolts or clamp that anchors the die in place loosen up. The entire die assembly may also shift, carrying the die with it. A horizontal misalignment can be stable or dynamic. In a dynamic misalignment, the extent of a misalignment can grow or shrink. The direction of the misalignment can also change from one strike to the next. A loose die or die assembly can oscillate in opposite directions or spontaneously return to a centered position.

If a horizontally misaligned hammer die collides with the anvil die, you end up with a horizontally misaligned die clash. If the misalignment was towards the south, the clash marks on the hammer die are positioned towards the north, relative to the southern arc of the design rim.