Katana is the word for "sword" in the Japanese language. A curved, single-edged sword traditionally used by the samurai. The katana was primarily used for cutting, although it's curvature is generally gentle enough to allow for effective thrusting as well. Though it is intended for use with a two-handed grip, many extant historical Japanese sword arts include at least one or two single-handed techniques. It is traditionally worn edge up.
You may attack to areas you just blocked. Your non-special attacks that cover only one grid deal one less damage.