Originally Posted by Priestess Kikyo
In the anime and manga series Naruto a jutsu (術, "Technique" or "Skill") is a general term referring to any technique a ninja might use that not any ordinary human could naturally imitate. Jutsu rely on the manipulation of chakra - consisting of the body energy inherent in the trillions of cells in the human body and the spiritual energy gained from exercise and experience - by various methods, the most common of which is hand seals. In some cases the line between a simple action and a Jutsu is blurred and vague, allowing for some humor (Uzumaki Naruto: "What? How did you get loose?!" Uchiha Sasuke: "Rope Untying no Jutsu. It's basic stuff.")
Jutsu are usually the product of channeling chakra to a certain part or parts of the body (through the inner coil system, which is to chakra as blood vessels are to blood) and then manipulating it to create an effect which wouldn't be possible otherwise. If the inner coil system malfunctions or is blocked in any way, it is impossible to perform any jutsu at all.
The English version of the Naruto manga has English names for the attacks, which are often stated with the attacks' Japanese names in translations starting in 2005. The North American Naruto fanbase typically prefers the Japanese names. In the English TV dub, a different set of attack names is used Generally speaking, jutsu are divided into three categories: Taijutsu (Body techniques), Genjutsu (Mind techniques) and Ninjutsu (Techniques that rely on sources beyond those). Besides these main categories there is another, more specific category: Fūin jutsu (Sealing techniques).
Besides being either Ninjutsu, Taijutsu or Genjutsu a jutsu can also be "Hiden" (秘伝, "Secret"). Hiden jutsu are jutsu passed down from generation to generation within some clans.
There is technically another category called Kinjutsu (禁術, "Forbidden Techniques"), but it refers not to the type of the jutsu but to the fact that it is forbidden to learn or perform it. A technique can be categorized as kinjutsu if it either causes great harm to the user if overused, such as Rock Lee's Lotus techniques, or if the techniques are dark or sinister in nature, such as many of Orochimaru's skills.
There are also Kekkei genkai. These are not really jutsu, but special, genetically inherited abilities like the ability to copy other jutsu or to merge your body with other bodies. Kekkei genkai abilities that work via the user's eye are called Dōjutsu (瞳術, "Pupil Techniques").
Some jutsu are based on Kekkei Genkai, like Tsukuyomi.
There are seven different ranks in jutsu:
S-rank: Secret: extreme level jutsu
A-rank: Kinjutsu: ultra high level jutsu
B-rank: Jōnin level jutsu
C-rank: Chūnin level jutsu
D-rank: Genin level jutsu
E-rank: Academy student level jutsu
No rank: Jutsu relying on bloodline limits or other unique abilities of the users, including Hiden jutsu Name: Byakugan, 白眼, literally "White Eye", Viz "All Seeing white Eye"
Type: Dōjutsu, No Rank, Supplementary, All ranges
Users: Hyūga Hinata, Hyūga Neji, Hyūga Hiashi, Hyūga Hanabi, Hyūga Hizashi (deceased)
The power and effectiveness of the Byakugan varies from person to person, but in the most advanced cases (such as that of Hyūga Neji), a Byakugan user has a 360 degree field of vision, with the exception of a small blind spot behind the user's first thoracic vertebrae (as stated in the manga), and can also see the minuscule chakra pressure points (tenketsu, 点穴). With the use of certain hand seals, it also has Telescopic and X-ray vision. The Byakugan is the key to Konohagakure's strongest Taijutsu, the Jūken, as it allows the user to see the chakra circulatory system of an opponent. It is to be noted, however, that the Byakugan is a seeing eye that lacks the power of analysis. Each level of its insight can therefore be mystified by proper means. This is demonstrated in an anime filler arc by Ranmaru, who created false chakra circulatory systems through the use of a dōjutsu (possibly a bloodline limit), causing the Byakugan to see inanimate objects as people and the objects themselves at the same time. However, it is not considered canon in a filler episode that a Byakugan user is unable to see the workings of such an "illusion". Name: Makyō Hyōshō, 魔鏡氷晶, literally "Demonic Mirror Ice Crystals" (a.k.a. "Demonic Ice Mirrors"), Viz "Secret Art of Water Ice Crystal Magic Mirror Technique" English Tv By Viz " Crystal Ice Mirrors"
Type: No rank, Offensive, Short to mid-range (0-10m)
This jutsu uses ice to create mirrors surrounding the opponent. These mirrors are harder than steel, and cannot just be simply broken through or melt. The jutsu user can travel instantaneously between these mirrors and attack while in movement, making it impossible to fend from the user's attacks or to go even on the offensive because to the human eye, the opponent can't even see where the user is going to attack from due to .
Haku's Makyō Hyōshō had never been defeated before his fight with Uzumaki Naruto and Uchiha Sasuke, when Naruto used the Kyūbi's chakra to break through the mirrors.