Jujutsu is basically a form of self defense is defensive and take advantage of "Yawara-gi" or techniques that are flexible, where the attack of the opponent are not faced with force, but by way of "cheating" opponent for the attack power can be used to beat himself. From this Jujutsu martial arts, was born a few other martial arts that have a similar defensive concept, namely aikido and judo, both also from Japan.
Jujutsu consists of a variety of flow (Ryuha), but the outline is divided into two "styles", namely traditional and modern. Movement of the two kinds of "style" Jujutsu is almost the same, but modern Jujutsu moves have been adapted to the situation of self defense in modern times, while the traditional Jujutsu moves usually reflect the current situation of self-defense in the respective created stream Jujutsu. For example, Jujutsu which was created in the Sengoku Jidai era (prior to the Tokugawa Shogunate in power) emphasized the fight on the battlefield by wearing armor (called yoroi Kumi Uchi), while those created in the Edo period (after the Tokugawa Shogunate in power) emphasis on self-defense using everyday wear (Suhada Jujutsu).
Jujutsu techniques to outline consisting of atemi waza (attacking the weak part of the opponent's body), kansetsu waza / gyakudori (joint locking the opponent) and nage waza (knockdown). Each flow Jujutsu has his own way to perform the techniques mentioned above. The techniques are born of self-defense method of the Samurai (warrior ancient war) when they lost his sword, or do not want to use the sword (eg because they do not want to injure or kill the opponent).
The flow of the oldest in Japanese Jujutsu is the Takenouchi-ryu, founded in 1532 by Prince Takenouchi Hisamori. Other streams include the famous Shindo Yoshin-ryu, founded by Matsuoka Katsunosuke in 1864, Daito-ryu, founded by Takeda Sokaku in 1892, Hakko-ryu, founded Okuyama Ryuho in 1942, and many other streams.