Name: Eight Gates (八門, Hachimon; English TV "The Eight Inner Gates")
Users: Maito Gai, Rock Lee, Kakashi Hatake
Debut (Anime):Naruto Episode 49
Debut (Manga): Chapter 85
The Eight Gates are eight specific points on a person's Chakra Pathway System. They limit the overall flow of chakra within a person's body. The basis for the idea of the chakra gates comes from the body's limits on the functions within it. This makes the body much weaker, but it keeps the body from expiring too soon. By opening these gates, the user can surpass their own physical limits at the cost of extreme damage to their own bodies.
Rock Lee is able to open the first five gates. Gai, who taught Lee the skill, is able to open at least six. Kakashi can open at least one gate, as shown during Kakashi's one-handed rock climbing where a shot of his brain shows the relevant point activating, as well as in his usage of the Front Lotus.
The state of having all Eight Gates open is known as Eight Gates Released Formation (八門遁甲の陣, Hachimon Tonko no Jin). Any shinobi who activates this state will temporarily gain powers greater than a Kage, but they will die because of the damage done to their body. However, in Naruto Shippūden 2: Bonds, Shinnō managed to use a technique that allowed him to open all the gates without any drawbacks.
Gate of Opening (開門, Kaimon) located in the brain. Releases the instinct restraints on the bodies muscle. Unlocking the gate allows the user to use the Front Lotus.
Gate of Healing (休門, Kyūmon; English TV "The Gate of Rest") located in the brain, raises the user's stamina.
Gate of Life (生門, Seimon) located on the spinal cord. Releases the limit on the nervous system allowing information to travel at a much faster rate. A side effect is that the user's skin turns red. Allows the user to use the Reverse Lotus.
Gate of Pain (傷門, Shōmon), located on the spinal cord. Increases the user's speed and power. May cause muscles tissue to tear on use.
Gate of Limit (杜門, Tomon; English TV "The Gate of Closing"), per above.
Gate of View (景門, Keimon; English TV "The Gate of Joy"), per above. Allows the user to perform the Morning Peacock. Opening of this gate releases such large amounts of chakra that it can cause nearby water bodies to form a vortex around the user.
Gate of Wonder (驚門, Kyōmon; English TV "The Gate of Shock"), per above. In the video games, allows the user to perform the Eternal Chaotic Dance.
Gate of Death (死門, Shimon) opens the final gate located at the heart and uses up all of the body's energy. It makes the heart pump at maximum power and exceeds the power of every other gate.