Shadow Blade

 
Prerequisite(s): One Shadow Hand stance.
 
Benefit: While you are in a Shadow Hand stance and attack with one of the discipline's preferred weapons, you can add your Dexterity modifier as a bonus on melee damage for attacks made with the weapon.
 
Special: Shadow Blade can be used in place of Weapon Finesse to qualify for a feat, prestige class, or other special ability. If this substitution allows you to gain a benefit that normally applies to all finesse weapons (those described in the Weapon Finesse feat description), it instead applies only to the Shadow Hand discipline's preferred weapons.
 
Source: Tome of Battle: The Book of Nine Swords