Whenever a weapon is thrown, this skill gets used. Knives are melee weapons, but if you throw a dagger at your opponent, this skill will be used. Grenades are a good reason to improve this skill. If you miss, the thrown object still has to end up somewhere. It's possible to throw a weapon and have it land right at your feet. If it's a knife, no big deal. If it is grenade, that's a really big deal. The maximum distance a weapon can be thrown is based on your character's Strength. This skill is used automatically when you attempt to throw a weapon.