Jujutsu, literally meaning the "art or science of softness", is a Japanese martial art consisting primarily of grappling techniques. Jujutsu evolved among the samurai of feudal Japan as a method for dispatching an armed and armored opponent in situations where the use of weapons was impractical or forbidden. Due to the difficulty of dispatching an armored opponent with striking techniques, the most efficient methods for neutralizing an enemy took the form of pins, joint locks and throws. These techniques were developed around the principle of using an attacker's energy against him rather than directly opposing it.
Today, jujutsu is still practiced both as it was hundreds of years ago and in modified forms for sport practice. The Olympic sport and martial art of judo was developed from several traditional styles of jujutsu by Kano Jigoro in the late 19th century. Brazilian Jiu-Jitsu ("Jiu-Jitsu" is a common informal romanization of "jujutsu") was developed after Mitsuyo Maeda taught judo in Brazil, but at that time was still referring to it as "Kano's jujutsu".
Jujutsu was first developed by Samurai but similar fighting forms have existed in Japan for centuries. The first references to unarmed combat arts or systems is in the earliest purported historical records of Japan, the Kojiki (Record of Ancient Matters) and the Nihon Shoki (Chronicles of Japan), which relate the mythological creation of the country and the establishment of the imperial family. Other glimpses can be found in the older records and pictures depicting sumai (or sumo) no sechie, a rite of the Imperial Court in Nara and Kyoto performed for purposes of divination and to help ensure a bountiful harvest. There is a famous story of a warrior Nomi no Sekuni of Izumo who defeated and killed Tajima no Kehaya in Shimane prefecture while in the presence of Emperor Suinin. Descriptions of the techniques used during this encounter include striking, throwing, restraining and weaponry.
These systems of unarmed combat began to be known as Nihon koryu jujutsu (Japanese old-style jujutsu), among other related terms, during the Muromachi period (1333-1573), according to densho (transmission scrolls) of the various ryuha (martial traditions) and historical records. Most of these were battlefield systems to be used with the more common and vital weapon systems. These fighting arts had various names, including kogusoku, yawara, kumiuchi, and hakuda, all under the general description of Sengoku jujutsu. They were not systems of unarmed combat, but means for an unarmed or lightly armed warrior to fight a heavily armed and armored enemy on the battlefield. Ideally, the samurai would be armed and would not need to rely on them.
Methods of combat (as just mentioned above) included striking (kicking and punching), throwing (body throws, joint-lock throws, unbalance throws), restraining (pinning, strangulating, grappling, wrestling) and weaponry. Defensive tactics included blocking, evading, off-balancing, blending and escaping. Minor weapons such as the tanto (dagger), ryufundo kusari (weighted chain), kabuto wari (helmet smasher), and kakushi buki (secret or disguised weapons) were almost always included in Sengoku jujutsu.
In later times, other koryu developed into systems more familiar to the practitioners of Nihon jujutsu commonly seen today. These are correctly classified as Edo jujutsu (founded during the Edo period): they are generally designed to deal with opponents neither wearing armor nor in a battlefield environment. Most systems of Edo jujutsu include extensive use of atemi waza (vital-striking technique), which would be of little use against an armored opponent on a battlefield. They would, however, be quite valuable in confronting an enemy or opponent during peacetime dressed in normal street attire (referred to as "suhada bujutsu"). Occasionally, inconspicuous weapons such as tanto (daggers) or tessen (iron fans) were included in the curriculum of Edo jujutsu.