Improved Grapple( Oriental Adventures, p. 63)
You are skilled in martial arts that emphasize holds and throws.
Improved Unarmed Strike (PH) ,
If you hit with an unarmed strike, you deal normal damage and can attempt to start a grapple as a free action without provoking an attack of opportunity. No initial touch attack is required. You can deal normal damage while grappling, rather than subdual damage, without suffering a penalty on your grapple check.
Characters without this feat make a melee touch attack to grab their opponent and provoke an attack of opportunity when doing so. They also suffer a —4 penalty on their grapple checks when trying to inflict normal damage in a grapple.