Very little is more frustrating to an archer than firing a well-aimed shot at his target, only to watch the arrow burst into splinters on a helmet or breastplate -- or, worse, a stray piece of jewelry that happens to be in the way. This skill trains you to selectively aim at parts of the body that are not covered by armour, without lowering the odds of a successful shot. In the case of full coverage, this skill helps you find chinks or gaps between the pieces, which is much harder to do.