Ninjutsu is a term referring to almost any technique which allows the user to do something that they otherwise would be incapable of doing, including the usage of weapons. Unlike genjutsu, which makes the opponent see illusions, the effects of ninjutsu are real. They vary greatly in purpose, with the simpler ninjutsu serving such tasks as transforming the user or allowing them to evade attacks. These techniques are often second-nature for experienced shinobi, who can use them at will. More complex ninjutsu manipulate one's surroundings or utilize the elements, respectively serving such tasks as healing others or manipulating nature transformations.Ninjutsu, most of the time, relies on chakra and hand seals to be effective. The hands are put in sequential positions that molds and manipulates chakra in the necessary manner to perform a technique. This is not always needed, however, and some techniques become second nature to experienced ninja, after which they can perform them at will. When creating a ninjutsu, the two methods of manipulating chakra are referred to as shape transformation and nature transformation:
1. Shape transformation deals with controlling the form, movement, and potency of chakra.
2. Nature transformation usually deals with changing the physical properties of chakra into an element.
These two methods can be implemented separately or together in order to create a ninjutsu.
Chakra is essential to even the most basic technique; it is the molding of the physical energy present in every cell of the body and the spiritual energy gained from exercise and experience. Once molded, it can be channeled through the chakra circulatory system, which is to chakra as the regular circulatory system is to blood, to any of the 361 chakra points (called tenketsu) in the body. Through various methods, the most common of which is hand seals, the chakra can then be controlled and manipulated to create an effect that would not be possible otherwise, such as walking on water, exhaling fire or creating illusions. By molding different ratios of the two energies, new colors and much stronger types of chakra can be formed. Most ninja have a natural affinity to one type of chakra, but they have the capacity to create elemental chakra apart from their own affinity. There are five basic types, each stronger and weaker to another, but their relations, weaknesses, and strengths to each other are all explored. There is also the dealing of Yin and Yang and the balance of mental and physical energies. In addition to these five elements, certain kekkei genkai can mix elemental chakra to form new natures, for example it is possible to mix water and wind into ice. While many ninja can use more than one type of chakra, very few are able to use them simultaneously.
Shinobi, otherwise referred to as ninja in the English translation of Naruto, are the primary focus and the main military power in the series. A female ninja is known as a kunoichi. Most come from a hidden village, of which some come from specialized ninja clans, and will perform missions for a fee. These missions can include: doing manual labor, acting as escorts, gathering secret information, retrieving stolen items, carrying out assassinations, etc. In times of war, ninja will come together to defend their villages and land. The clearest characteristic of a shinobi is their ability to manipulate chakra to create and use techniques. Shinobi are expected to be loyal to their villages for life, and any defectors are considered to be missing-nin, and will be marked for death.