Short Clock
From AmtWiki
A fighting system which attempts to compromise between Atomic Clock and Shot In Motion, which allows for a short time period for a shot to finish, usually defined as a half-second. Also defined as phonetic clock, or any blow that strikes within the sound made by the first. This is a significantly different compromise than the one put forth in 6.1, which is Hybrid.
This is the new system defined under 6.5.