Wood Release: Four-Pillar Prison Technique - a ninjutsu in which the user converts chakra into wood underground and makes it grow rapidly, forming a wooden prison. The size and shape of the structure depend on the user's intent: one can create both a small cage and a huge dungeon, regulating the chakra expenditure. The wood is covered with a layer of chakra, which makes it extremely difficult to destroy. The technique is suitable for holding prisoners during war or as a disciplinary measure for guilty allies.