Needs review
Source: Oriental Adventures

Description: You have learned the correct way to apply pressure to render an opponent unconscious.

Prerequisites: Improved Unarmed Strike, Improved Grapple, Stunning Fist

If you pin your opponent while grappling and maintain the pin for 1 full round, at the end of the round your opponent must make a Fortitude saving throw (DC 10 + 1/2 your level + your Wisdom modifier). If the saving throw fails, your opponent falls unconscious for 1d3 rounds.