Four Symbols Seal

This is a sealing technique based on the fūinjutsu of Uzushiogakure. The sealing formula is carved into a human body or an object, and is mainly used when a giant enemy or evil spirit needs to be sealed. To use it, it is necessary for the user to have great ability.

When two Four Symbols Seals are used together, they form the Eight Trigrams Sealing Style. When Minato sealed the Nine-Tailed Demon Fox into Naruto Uzumaki, he left an opening at the space where the two four symbols seals meet, allowing the Nine-Tails' chakra to merge with Naruto's chakra. Minato also left behind a key with Gerotora, which would be used to tighten the seal when it weakened. Naruto would eventually use the key to gain control over the Nine-Tails' chakra.

The seal also appears on the stomach of the users of the Dead Demon Consuming Seal after the target and the user's own soul is sealed in the death god's stomach, such as what happened to Hiruzen Sarutobi after sealing Orochimaru's arms.

Trivia

 * According to Killer B, this is a high-quality seal and is more durable compared to the Iron Armour Seal that holds the Eight-Tails.
 * This seal is the opposite of the Reverse Four Symbols Sealing Technique.