Iron Fist Style (3.5e Feat)
From D&D Wiki
 Iron Fist Style [Ki Manipulation]
The Iron Fist Style is a unarmed combat style which employs powerful blows to injure and break an opponents body.
Benefit: You must declare you are using this feat before your attack. You deal +1d6 damage with your unarmed strike.
Ki Point Cost: 1 Point per Attack.
Special: If you take this feat, you may not take the Gentle Palm Style feat.
This feat can be used more then once a round unlike other Ki Manipulation feats.