This seal is given to all branch house members in the Hyuga clan by members of the main house. Its main purpose is to seal their Byakugan ability when they die, preventing an enemy from learning its secrets. Its secondary purpose is to control the branch house, since it can be activated at will by a main house member with a hand seal that only they know about, to destroy the wearer's brain cells. This seal is commonly referred to as the "Caged Bird Seal" by fans, due to Neji calling himself a "caged bird" in conjunction with the sealing progress.