Chakra

Simplified diagram of chakra generation mechanics

Chakra (チャクラ chakura) is the basic energy source necessary for ninja in Naruto to perform most jutsu. Millennia before the main story, people were originally born without chakra until a young woman named Kaguya Ōtsutsuki stole the fruit of the Shinju and ate it to obtain the power of chakra to end a war in her time. Her son, the Sage of the Six Paths, was born with the ability to produce chakra by combining physical energy (身体エネルギー shintai enerugī), drawn from the trillions of cells that make up the human body, and mental energy (精神エネルギー seishin enerugī), gained through experience and meditation.^[7] Once created, chakra moves throughout the body in a manner similar to the circulatory system and is delivered to one of 361 chakra release points.^[8] By performing a sequence composed of any of twelve different hand seals, chakra can then be manipulated to create supernatural effects, such as walking on water.^[7] The method of chakra production is passed on to the sage's various descendants, both direct and indirect, along with other ninja.

During Part II of the series the concept of nature transformation (性質変化 seishitsu henka), altering the quality of chakra, is introduced. Nature manipulation allows ninja, following certain training, to convert their chakra into one of five elements: earth, water, fire, wind, and lightning.^[9]Each element is predominant and subordinate to different elements; for example, fire is weak against water, but can easily counter and even gain strength when used against a wind-based jutsu and earth is weak against lightning based jutsu.^[10]Most ninja have a natural affinity for one of the five elements, allowing them to use jutsu of that type with greater ease. Ninja with an affinity for fire, for instance, will be able to breathe fire much sooner than they will be able to manipulate water.^[9]

Skilled ninja can learn how to use other elements; ninja of the Jonin (lit. "high ninja") rank are typically able to manipulate at least two elements. Kakashi Hatake has been shown using all 5 different elements in the Naruto series. Although these ninja can use their different elements separately with little effort, combining the two elements is impossible for ninja who do not have a genetic predisposition for it. Ninja with one of these genetic abilities can mix two specific elements to create an entirely new one. Haku, an antagonist introduced at the start of the series, can mix water and wind to create ice. Wood Style, a combination of earth and water unique to the First Hokage, Danzo, and Yamato, allows the user to produce wood.^[11] There is also the Yin-Yang Style and its splintered forms, Yin Style and Yang Style, that only few master, which can counter the other chakra natures.

Eight Chakra Gates

The Eight Gates (八門 Hachimon, English anime: "The Eight Inner Gates") are eight specific points along the chakra circulatory system that limit the overall flow of chakra within a person's body, which prevents the body from expiring too soon. Ninja devised the Eight Gates Released Formation (八門遁甲の陣 Hachimon Tonkō no Jin, English TV "Eight Inner Gates Formation") to surpass their own physical limits at the cost of various levels of damage to their own bodies. Each additional gate grants the user new levels of strength with additional injuries; by opening all eight gates the user will become invincible in battle, but their body will be so damaged in the process that they will die afterwards. Having learned the release technique from his father, Might Guy taught Rock Lee to open his first five gates during Part I of the series; according to Kakashi Hatake, this is a very remarkable feat as he himself can only open the first gate.^[12] Guy goes further by activating all the way to the eighth gate during Part II, although he states that activating it would kill him.^[13] In the Naruto Shippūden 2: Bonds movie, the villain Shinnō mentions opening the eight gates when gaining the "perfect body" from his dark chakra transformation

1. Gate of Opening (開門 Kaimon): located in the brain, the gate removes the brain's restraints on the muscles to use 100% of their strength.
2. Gate of Healing (休門 Kyūmon, English TV "Gate of Rest"): located in the brain, it forcibly increases one's physical strength and temporarily empowers the body.
3. Gate of Life (生門 Seimon): located on the spinal cord, its release causes the skin to turn red from increased blood flow.
4. Gate of Pain (傷門 Shōmon): located on the spinal cord, its release increases the user's speed and power at the cost of potential tearing in muscle tissue.
5. Gate of Limit (杜門 Tomon, English TV "Gate of Closing"): located in the abdomen, its release further increases the user's speed and power.
6. Gate of View (景門 Keimon, English TV "Gate of Joy"): located in the stomach, its release further increases the user's speed and power to the point that bodies of water would converge around the user due to the enormous amounts of chakra being emitted. The technique associated with this gate is Asakujaku (朝孔雀, Morning Peacock), kicking an opponent in the air to deliver a barrage of punches so fast that the air around the fist is set ablaze and a peacock-like fan of flames is formed around the opponent.
7. Gate of Wonder (驚門 Kyōmon, English TV "Gate of Shock"): located below the stomach, its releases causes every pore of the user's body to emit a turquoise-colored sweat that instantly evaporates and gives the illusion of a chakra coating. The side effects of opening the seventh gate are that the user's muscle fibers become fragile to the point that anything can rip them to shreds. The technique associated with this gate is Hirudora (昼虎, Daytime Tiger), a single punch that creates air pressure around the fist in the form of a tiger to land a death blow.
8. Gate of Death (死門 Shimon): located at the heart, its release expends all of the body's energy while the sweat becomes a crimson color. With the heart pumping at maximum power, this gate makes the user the most powerful figure in a battle yet kills them shortly after. The two techniques associated with this gate are Sekizō (夕象, Evening Elephant), a series of punches in which the shockwaves produced resemble giant elephant feet, and Yagai (夜ガイ, Night Guy), in which the user manifests a dragon-shaped aura and performs a kick which obliterates the targets.