Eight Gates (Ten Tails)

The Eight Gates are eight "gateways" located along one's chakra circulatory system that limit the flow of chakra in the body.

Usage
By undergoing rigorous training, once can learn to activate and eventually control the eight gates located along their chakra network. Doing so can allow the user to drastically increase their own power, vastly exceeding any previous limitations they had, at the cost of doing great physical harm to their bodies.

Many of the shinobi from Konohagakure can open one or more of the gates. In the Land of Mountains, specifically its hidden village of Yamagakure, only Tora Uchiha is known to have access to the gates; being capable of opening all eight.

The state of having all Eight Gates opened is known as the. Any shinobi capable of using such a formation can temporarily access power greater than that of a Kage-level shinobi, but the cost of such power is the user's life.

In addition to the tremendous power unleashed upon opening the gates, the user also undergoes a physical transformation, the most common of these being a darkening of the skin and bulging veins. Upon opening the seventh gate, however, a powerful green aura of sweat is released from the body, which has been easily mistaken as chakra in the past. The eighth gate produces a similar effect, releasing red steam which has been referred to by Madara Uchiha as.

Gates

 * , located in the brain. This gate removes the restraints of the brain on the muscles so 100% of their strength can be used whereas normally, a person can only use 20% of their muscles' strength to keep them from disintegrating.
 * , located in the brain. Forcibly increases one's physical strength and temporarily re-energises the body.
 * , located on the spinal cord. The increased blood flow turns the skin red.
 * , located on the spinal cord. Increases the user's speed and power. May cause muscle tissue to tear on use.
 * , located in the abdomen. Increases the user's speed and power.
 * , located in the stomach. Increases the user's speed and power. Opening of this gate releases such enormous amounts of energy that it can cause nearby water bodies to form a vortex around the user.
 * , located below the stomach. Further increases the user's speed and power. Those who open this gate will secrete glowing green sweat from every inch of their body which immediately evaporates from their own heat energy, creating an aura which people mistake as a chakra coating. Unfortunately, the side effects of opening the gate are that the user's muscle fibres are ripped to shreds, causing intense pain if anything or anyone touches them.
 * , located at the heart. The user's blood will emanate from their body as a flaming aura of red steam that also emanates from their hair and eyebrows. Releasing this gate uses up all of the body's energy. It makes the heart pump at maximum power and exceeds the power of every other gate. Opening this gate grants the user near-immeasurable power, but comes at the expense of the user's life.

Senjutsu Influence
A shinobi capable of preforming Sage Mode can further enhance their use of the Eight Gates. The result is an immensely powerful chakra and further physical transformations. In addition to the transformations created by Sage Mode, the user's hair will appear to be gold, and their bodies emit a glowing golden sweat, rather than green. Ryun Uchiha has commented that, though his younger brother Tora is weaker than him, upon use of this variation of the Eight Gates, he easily closes the gap. Sage Mode also allows the user to open the eighth and final gate without fear of dying, however, such protection only lasts while the user has senjutsu chakra molded within them. Should Sage Mode expire before then, the user will still suffer the drawbacks of the Eight Gates Released Formation.

Trivia

 * The senjutsu-enhanced Eight Gates was inspired by the idea of the from Akira Toriyama's Dragonball manga.