Gravity Seal (Yakushimi)

The Gravity Seal (比重印, Hijūin, Literally meaning: Gravity Seal) is the Hiden of the Sengoku Clan, which revolves around the concept of increasing the gravity experienced by the members for purpose of training, therefore mitigating the need for Weights.

Initially invented by Ryun Sengoku for the sole purpose of making training even harder on himself, the Gravity Seal is said to be an enigma of Chakra Control, requiring exceptionally precise Chakra Control to a focal point of the body, therefore creating the seal and causing it to take effect. It works in increments, as the standard Gravity constant of Earth is 9.8 meters per second, adding on the first level of the Seal: a times-two Gravity Seal, would cause the user to experience 19.6 meters per second, and then a times-three Gravity Seal would cause 29.4 meters per second, so on, up to the highest known limit: twenty times Earth's gravity.

Likewise, as the Gravity Seal can be applied to oneself, due to it being a Fūinjutsu, it can be applied to other people, causing them to suddenly be weighed down and become incapable of simply moving their limbs for long periods of time without experiencing exhaustion, unlike members of the Sengoku Clan, who are branded with the Seal at 4 years of age, with the multiplier being twice Earth's gravity.