A Four Symbols Seal is used to seal a large enemy or an evil spirit into a target, such as an object or a human's body. A stronger seal is created if two Four Symbols Seal are used; this is called the Eight Trigrams Sealing Style. If the Four Symbols Seals do not completely overlap with each other, this allows the enemy/spirit's chakra to merge with whoever they've been sealed into. In the anime, this seal is intended to encourage tailed beasts to aid the jinchūriki they've been sealed within, as the more they provide chakra, the weaker the seal becomes, and thus the better their chance of freedom .