Nature Transformation

Nature Transformation (性質変化, Seishitsu Henka) is an advanced form of chakra control and a technique that is pivotal for the manipulation chakra and the creation of new jutsu. While Shape Transformation changes the shape and movement of chakra, elemental nature transformation changes the actual nature of the chakra, altering its properties and characteristics. It is notable that few shinobi can use both shape manipulation and nature manipulation.

Nature Manipulation/Transformation is one of two necessary techniques for creating a jutsu, its counterpart being Shape Transformation. Nature Manipulation entails the molding and defining of one's chakra into a innate type of chakra nature.

Basic Types
There are five basic types into which the nature of chakra can be transformed, called the Five Elements Nature Transformations (五大性質変化, Godai Seishitsu Henka). These five types are also called elements and are not only the origin of the names of the Five Great Shinobi Countries, but also the foundation of all elemental ninjutsu. The five basic natures are all connected to each other in a circle, each being weaker than one and stronger than another.

These elements allow for elemental ninjutsu to be performed: Basically, this means that if an elemental jutsu is put against an elemental jutsu of the same level, but of a stronger nature, then the jutsu with the superior nature will prevail. However, a jutsu with a weaker nature can overpower a jutsu with a stronger nature if the former is of a higher level.
 * Fire (火, Hi) natured chakra allows for Fire Release (火遁, Katon), which is strong against Wind but weak against Water.
 * Wind (風, Kaze) natured chakra allows for Wind Release (風遁, Fūton), which is strong against Lightning but weak against Fire.
 * Lightning (雷, Kaminari) natured chakra allows for Lightning Release (雷遁, Raiton), which is strong against Earth but weak against Wind.
 * Earth (土, Tsuchi) natured chakra allows for Earth Release (土遁, Doton), which is strong against Water but weak against Lightning.
 * Water (水, Mizu) natured chakra allows for Water Release (水遁, Suiton), which is strong against Fire but weak against Earth.

Affinity
In general, every person has chakra that has an affinity towards one of these types, a characteristic that seems to be genetic, since whole clans sometimes share the same affinity. Most members of the Uchiha clan, for example, had an affinity towards the Fire nature.

To find out what affinity someone has, pieces of paper made from a special type of tree (that are grown and fed with chakra) are used that react to even the slightest hint of chakra in any of a number of ways, depending on the nature latent in the chakra.

The Chakra Paper reactions are as follows: This affinity makes it easier to learn how to create and control the nature in question, although even with an affinity this process will usually take any number of years. Shinobi are not limited to the nature they have an affinity to, though. By the time they reach the rank of Jōnin, most shinobi have mastered two natures. However, because of the difficulty of mastering a nature and the time required to learn it, it is almost impossible to master all five natures in normal way.
 * Fire: the Paper will ignite and turn to ash.
 * Wind: the Paper will split in two.
 * Lightning: the Paper will crumple up.
 * Earth: the Paper will turn to dirt.
 * Water: the Paper will become damp.

Advanced Types
Besides the five basic nature types, there are several more advanced types. By using two basic types simultaneously, one can create a completely new nature with unique properties, and is referred to as a "elementally-recomposed nature type". Doing this requires a special ability and such abilities are rarely seen outside a kekkei genkai.

So far, eleven natures have been shown:
 * The Ice (氷, Kōri) nature, is created by simultaneously combining the Water and Wind natures. This nature allows for the use of Ice Release (氷遁, Hyōton) ninjutsu. Ice Release has been shown as being strong against Fire Release.
 * The Wood (木, Ki) nature, is created by simultaneously combining the Earth and Water natures. This nature allows for the use of Wood Release (木遁, Mokuton) ninjutsu.
 * The Lava (溶岩, Yōgan) nature, is created by simultaneously combining the Fire and Earth natures. This nature allows for the use of Lava Release (熔遁; 溶遁, Yōton).
 * The Blaze (炎, Honō) nature, originates from the flames of Amaterasu and allows the use of Blaze Release (炎遁, Enton) ninjutsu. It is unknown what this nature entails.
 * The Storm (嵐, Arashi) nature, is created by simultaneously combining the Lightning and Water natures. This presumed nature allows for the use of Storm Release (嵐遁, Ranton) ninjutsu.
 * The Boil (沸騰, Futtō) nature, is created by simultaneously combining the Water and Fire natures. This nature allows for the use of Boil Release (沸遁, Futton) ninjutsu.
 * The Dust (塵, Chiri) nature, is created by simultaneously combining the Earth and Wind natures. This nature allows for the use of Dust Release (塵遁, Jinton) ninjutsu.
 * The Iron nature, is created by simutaneously combining the Lightning and Earth natures. This nature allows for the use of Iron Release (Satetsu) ninjutsu.