From Wkipedia:
Originally, Aizen carried a zanpakut? called Ky?ka Suigetsu (?????, literally “Mere shadow”). Ky?ka Suigetsu’s Shikai ability Kanzen Saimin (?????, literally “Complete Hypnosis”), activated with the command “shatter” (??? kudakero?), is effective if the target watches the Shikai sequence once and thus can fall under Aizen’s deception any time he wishes.
And here a scene from anime
http://www.youtube.com/watch?v=XtOsA7qLSfU
