Chakra

Chakra (チャクラ, chakura) is the result of moulding of two different energies - the physical energy (身体エネルギー, shintai enerugī) present in every cell of the body and the spiritual energy (精神エネルギー, seishin enerugī) gained from experience and exercise. Whilst all living being produce some level of chakra, it is possible to create more by moulding those two energies. By manipulating chakra - typically through hand seals - a person can perform jutsu.

Through jutsu, a person can do what would normally be considered impossible - walk on water, turn into earth and move as fast as lightning. Because of its amazing capabilities, chakra is used extensively by shinobi. It is very rare for a person to even become a shinobi without being able to control chakra, as before a technique can be used chakra must be channelled through the body's tenketsu, or chakra points.

Normal Chakra
Similarly to the body's cardiovascular system, the body has a chakra circulatory system. It carries chakra throughout the body, as all living beings produce and, in fact, need chakra. If their chakra levels run low, the individual will experience chakra exhaustion, which can cause the user to become tired. If they continue to use their chakra, they will not have enough to stay alive.

The threat of chakra exhaustion means that if one wishes to effectively use jutsu, they must undergo a great deal of training - not just to increase the amount of chakra they produce, but to learn how to conserve it when using jutsu. With training, a person can also learn to release chakra through their body's tenketsu, which allows them to perform jutsu. Though it can be released, chakra is normally invisible unless a very large amount of it is being released at once. This is a rare sight because releasing so much in most circumstances will lead to chakra exhaustion. If the person does not possess enough chakra, releasing that much will not even be possible thanks to the Eight Gates restricting the amount of chakra that can be released at once.

Chakra can, in a sense, be trained in order to increase its potential, but it is made up of two energies and both components are trained in different ways. "Physical energy" is present in the body's cells and can be increased through exercise and training, as well as by using stimulants. "Spiritual energy" is the being's mental power and is collected from their conciousness. Studying and meditation are among the methods used to train it. Performing techniques that use chakra can also train one's spiritual energy, as they are gaining experience. This method also allows them to become more proficient with the technique, and learn to use less chakra when performing it.

Almost all jutsu require chakra to use, with the exception being taijutsu. Those techniques are strictly physical and very rarely require the moulding of chakra. That is one of many reasons that shinobi will possess some level of skill in taijutsu.

Chakra Control
Chakra Control (チャクラコントロール, chakura kontorōru) refers to the control of chakra. Every living being has chakra, but in order to perform jutsu they must be able to mould and control it. As mentioned above, controlling chakra is a skill that must be learned through a lot of training.

In order to mould chakra, a person must collect both physical energy from their cells and spiritual energy from their conciousness. The two are then mixed to create chakra, and then moulded to perform a technique. Whilst it is possible to use a technique without mastering it, doing so can lead to the individual using more chakra than necessary and end up wasting some. Conversely, they could use too much or too little chakra, resulting in the technique performed not being as effective or outright failing. The Leaf Concentration, Tree Walking and Water Walking practices are among those used to teach chakra control to budding shinobi. Hand seals can also be used to control chakra more effectively, to the point that there are few jutsu that do not require at least one seal.

Creating ninjutsu requires two other types of chakra control in addition to the above: The two can be used separately or in conjunction to create a technique, though not many shinobi know how to use both effectively.
 * Shape Transformation refers to the control of the chakra's movement, form and potency.
 * Nature Transformation refers to the changing of chakra's physical properties into an element.

Senjutsu Chakra
Senjutsu chakra (仙術チャクラ, Senjutsu Chakura) is created from the mixture of three energies. In addition to the physical and spiritual energies found inside the body, it is possible for a person to also use the natural energy in the air and earth around them. The three energies must be equally balanced in the body, which means that a person with more chakra will be able to use more of it. Learning to use senjutsu chakra, however, is extremely difficult, if one can even find somebody to teach them in the first place.