Four Symbols Seal

This technique requires a great deal of talent to perform. The user applies the seal's formula to an object or a human's body, sealing a large enemy or an evil spirit within them. If two Four Symbols Seal are used, a stronger seal is created; 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. This is how the Nine-Tails was sealed into the body of Naruto Uzumaki.

The Four Symbols Seal is based on the fūinjutsu of Uzushiogakure's Uzumaki clan. According to Killer B, it is stronger than the Iron Armour Seal used to seal the Eight-Tails within him. The Four Symbols Seal is also left on the stomachs of those who perform the Dead Demon Consuming Seal.

Trivia

 * This technique has the opposite effect of the Reverse Four Symbols Sealing.
 * In the manga, after transferring Kurama's Yin-half into an incapacitated Naruto Uzumaki, Obito Uchiha was also shown reestablishing the former's two Four Symbols Seals.
 * In the anime, Orochimaru suited Mecha-Naruto with two Four Symbols Seals in order to take the Nine-Tails from Naruto.