Kyoka Suigetsu

Kyōka Suigetsu (mirror flower water moon). In its sealed form, it looks like a normal katana Kyoka Suigetsu's shikai has the ability to place anyone who sees it under a state of "Perfect Hypnosis" (kanzen saimin), after which Aizen can make them see, hear, and feel whatever he wants. According to Aizen, the hypnosis is unbreakable, even if the target is aware that they are hypnotized. The only way to avoid the effect is to not see Kyōka Suigetsu's shikai, making the blind Kaname Tōsen immune to its effects.