Martial art style developed by the Ninja during the 16th century. Ninjutsu teaches the art of beating your opponent without the use of any force, by showing the human body's weak points. Ninjutsu enables yourself to end a battle shortly after it began by breaking the enemy's bones or making him unable to move any more.

A traditional Japanese art of stealth, camouflage, and sabotage, developed in feudal times for espionage and now practiced as a martial art.

Developed in the 16th century during the Feudal era of the Japanese, it was created to combat the ever rising threat of the samurai. The art was specifically created to target weak joints within armour with a concentration of a high powered blow.

Now practically useless, it is used by morons who think that being a ninja is cool, when in reality, Chinese wushu owns everyone.

Ninjutsu is the collection of Martial ways learned by Ninja of fuedal japan. There is no magic involved-a misconception developed from the old days, where people didnt understance science the way ninja did, and labelled some things as magic. Ninjutsu consists of the Ninja Juhakkei, 36 ninja essensials such as
Bikenjutsu:Ninja's sword method (including Ninja-to, Odachi,Nodachi,Tachi and Nito-Ichi-Ryu)
Taijutsu: Ninja's fighting method (Togakure Ryu ect)
So-jutsu: spear technique
Naginata-jutsu:Halberd techniques
Bisento-jutsu:Battlefield halberd techniques
Kusarigama-Jutsu(Kyoketsu Shoge): Sickle and chain techniques
Rokushakubo-jutsu:6ft staff techniques (full staff)
Sanjaku Bojutsu + Jojutsu:Half and 3 quarter staff techniques
Shuriken-jutsu and Senban Nage Jutsu: Blade throwing
Kisha-jutsu:Archery from horseback
Inton-no-jutsu: Dissapearing techniques
Hokojutsu (Aruki):Stealth Walking techniques
Henso Jutsu:Disguise
Kakushi Buki-Jutsu:Secret weapons (Shuko, Sokko, Nekode ect)
Ninyaku-jutsu:Special medicines and drugs
Gunryaku-Heiho: Stratagies
Tenmon and Chimon: Stratagies using heaven and earth.
Taijutsu is usualy considered the most important of these (besides spiritual refinement) as it taught the ninja skills such as Sabaki (sword evasion) Taihenjutsu (acrobatics and rolling techniques+breakfalling) and fighting methods.
learning the bodys Kyusho (pressure points)
Throwing techniques (including lock-throwing)
Grappling techniques
Striking techniques (ect Shikan-ken, Boshi-ken)
Nearly all sources besides sources of the Genbukan, Bujinkan and Jinenkan are incorrect about Ninjutsu. Also, things like *Chakra* are a lot of rubbish. Kuji Kiri (hand symbols) do exist, there are 9 main and over 50 others, but they are EXTREMELY secret(the others besides the 9) so most people just make them up.

Ninjutsu is a large collection of different martial arts that was used by ninja. The ninja used 18 different martial arts called Ninja Juhakkei. These martial arts are...
Seishin-teki kyoyo(spiritual refinement)
Taijutsu(unarmed combat)
Ninjaken(sword techniques)
Bojutsu(stick and staff fighting techniques)
Shuriken(throwing blade technique)
Sojutsu(spear fighting)
Naginatajutsu(halberd fighting)
Kusarigamajustu(sickle and chain techniques)
Kayakujutsu(pyrotechnics and explosives)
Hensojutsu(disguise and impersonation)
Shinobi-iri(stealth and infiltration techniques)
Bajutsu(horsemanship)
Sui-ren(methods involving water)
Boryaku(military strategy and political manipulation)
Choho(espionage)
Intonjutsu(concealment and escape methods)
Tenmon(meterology, zoology)
Chimon(geography, zoology)
Also thngs like chakra is complete crap, and ninja weren't magical. This is something from the old days because many people didn't understand how ninja did their jobs.

its like ninja magic, cept without the wands...and the cauldron.......and frog eyes and stuff.

well, with an exception of naruto quirks and stuff, ninjutsu is a collection of techniques and styles that are used by ninja's for concealment, escape, disguise, medicine, archery, collecting information and etc. some skills include:

taijutsi (unarmed combat)
ninja ken (sword fighting)
Seishin-teki kyôyô (spiritual refinement)
Shurikenjutsu (throwing blades)
Hensôjutsu (disguise and impersonation)
Shinobi-iri (stealth and infiltration methods)
Intonjutsu (escaping and concealment)
Sui-ren (training in water)

A law of the Universe, that states that there is a finite amount of ninjutsu available to each side during any given battle. If there are many ninjas, they are all awarded a fraction of the total ninjutsu, or 1/N where N is the number of ninjas present in the fight.

This is the reason why hordes of ninja warriors will be dispatched relatively easily, whereas the lone ninja is almost unstoppable.

The gentle art of folding clothes while people are still inside them