Strength of a Hundred Seal

A seal which is reputed to be the pinnacle of chakra control. By storing a vast amounts of chakra over an extended period of time into a specific point on their body — usually the forehead — the user creates this seal, which manifests in the form of a rhombus-like marking. Once the seal is formed, the user's already impressive chakra control allows them to perform techniques without any wasted energy. When released, the seal will either spread across the user's face or wrap around their entire body. The stored chakra is then released into their body, greatly amplifying the power of their techniques.

By releasing the power of their seals, both Tsunade and Sakura were able to combine its power with Creation Rebirth and gain them access to the Ninja Art Creation Rebirth — Strength of a Hundred Technique. Their seals are also linked to Katsuyu, and as the slug noted, it too is supported by the seal.

It should be noted that once the seal is released, it will permanently remain in the centre of the user's forehead, presumably so that the user can keep on benefiting from its effects.

Trivia

 * When written as '白毫', byakugō means, which is a white swirl of fine hair on the forehead of the Buddha, represented in art by a spiral or a dot, or even a gem or pearl. It represents the third eye which allows one to see past the mundane world and into the divine world.
 * In the chapters published in Shōnen Jump, the seal was initially identified as . It was corrected in the tankōbon version.
 * Tsunade also uses a portion of the seal's chakra to maintain her youthful appearance.
 * In the fourth databook, it was stated that Mito Uzumaki also had this seal, which manifested as a diamond on her forehead.
 * Sakura spent three years storing chakra to form the seal, something Tsunade's first disciple, Shizune, noted that even she was unable to achieve due to the level of chakra control required.
 * In Naruto: Shippūden episode 408, it is further explained by Tsunade that because of the delicate nature for building up chakra required for this technique, a person is substantially drained of normal reserves of chakra, making it dangerous for one to perform surgery or battle. Sakura, however, found a way to divert a small portion of that built-up chakra back into her normal reserves.