Needs review
Source: Rokugan Campaign Setting

Description: You are capable of inflicting powerful unarmed attacks

Prerequisites: Improved Unarmed Strike, Base Attack Bonus +5, Fists of Iron

Required for: Shards of Earth (Unarmed)

If you spend an entire round preparing an unarmed attack (neither attacking nor moving) you can inflict extra damage equal to 1d6 times your strength modifier. If applied against an inanimate object all damage you inflict is doubled.