Jutsu

Jutsu, or skills/techniques, are the mystical arts a ninja will utilize in battle. To use a jutsu, the ninja will need to use their chakra. To perform a jutsu, the ninja will bring out and release the two energies of chakra. By forming handseals, the ninja is able manifest the desired jutsu. Because of the extensive number of hand seals and different combinations, there are thousands of potential jutsu to be discovered.

The Basics
There are three types of jutsu: Ninjutsu, Genjutsu, and Taijutsu. There are also Kekkei Genkai abilities which aren't jutsu, but inherited abilities passed down through certain clans (however, they can be used as base for certain jutsu, such as Haku's Demonic Ice Crystal Mirrors). There is also a fourth type of jutsu called senjutsu. Jutsu can also be attributed to certain parts of the body. (eg. Dojutsu is Jutsu of the eye.)

As an in-between stage, some ninjas can partially control their chakra. This means they can use their chakra, but not effectively control it, which results in poorly executed jutsu, and more importantly, running out of chakra early in a fight. To manipulate their chakra more easily, hand seals can be used. With these hand seals, users can control their chakra with higher efficiency, allowing them to execute their jutsu more effectively. Different jutsu require a different hand seals.

Ranks
Depending on the difficulty or skill necessary to perform a jutsu, they are ranked differently. There are six different ranks in jutsu: Kekkei Genkai and other unique abilities of users do not have a rank.
 * E-rank - Academy student level: E Rank Jutsu are learned by Academy Students which are the basic and most fundamental jutsu for all graduating ninja. (e.g. Clone Technique & Transformation Technique)
 * D-rank - Genin level: D Rank Jutsu are Genin level techniques and can be achieved by all Genin, though many ninja only learn their "type" of technique. (e.g. Earth Release: Double Suicide Decapitation Technique)
 * C-rank - Chunin level: C Rank Jutsu are based on Chunin level techniques though some Genin, like Sasuke Uchiha, can perform this and some Chunin cannot. (e.g. Fire Release: Great Fireball Technique)
 * B-rank - Jonin level: B Rank: B Rank Jutsu are Jonin level techniques but Naruto can also perform this technique, emphasizing his determination and high chakra levels. (e.g. Shadow Clone Technique)
 * A-rank - Kage level or Jonin level: A Rank Jutsu are Elite Jonin level and up, even including some Forbidden Techniques. The Chidori and the Rasengan, mastered respectively by Sasuke and Naruto, are A-ranked Jutsu.
 * S-rank - Secret, extreme level: S Rank are Secret, high class level techniques. Techniques of this rank are mostly known to only 1 or 2 ninja and are often forbidden.(e.g. Wind Release: Rasenshuriken)

Dojutsu
Dōjutsu (瞳術) are genetic ninja abilities that utilize the eyes, enabling them to percieve chakra in some form or another. Being a byproduct of specific kekkei genkai, dōjutsu are not classified as one of the major jutsu types. They do not require hand seals to use and sometimes facilitate in the use or defense against genjutsu, taijutsu and ninjutsu and then defeat his or her opponent. All known dōjutsu also provide the user with some otherwise incapable ability, such as an extended field of vision or predictive capabilities.