The term jū-jutsu was not coined until the 17th century, after which time it became a blanket term for a wide variety of grappling-related disciplines. Prior to that time, these skills had names such as “short sword grappling” (kogusoku koshi no mawari), “grappling” (kumiuchi), “body art” (taijutsu), “softness” (yawara), “art of harmony” (wajutsu, yawarajutsu), “catching hand” (torite), and even the “way of softness” ( jūdō) (as early as 1724, almost two centuries before Kanō Jigorō founded the modern art of Kodokan Judo).
Today, the systems of unarmed combat that were developed and practiced during the Muromachi period (1333–1573) are referred to collectively as Japanese old-style jujutsu (Nihon koryū jūjutsu?). At this period in history, the systems practiced were not systems of unarmed combat, but rather means for an unarmed or lightly armed warrior to fight a heavily armed and armored enemy on the battlefield. In battle, it was often impossible for a samurai to use his long sword, and would therefore be forced to rely on his short sword, dagger, or bare hands. When fully armoured, the effective use of such “minor” weapons necessitated the employment of grappling skills.
Methods of combat (as mentioned above) included striking (kicking and punching), throwing (body throws, joint-lock throws, unbalance throws), restraining (pinning, strangling, grappling, wrestling) and weaponry. Defensive tactics included blocking, evading, off-balancing, blending and escaping. Minor weapons such as the tanto (knife), ryofundo 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 jūjutsu (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 tantō (daggers) or tessen (iron fans) were included in the curriculum of Edo jūjutsu.
Another seldom-seen historical side is a series of techniques originally included in both Sengoku and Edo jujutsu systems. Referred to as hojo waza (hojojutsu, torinawa jutsu, nawa jutsu, hayanawa and others), it involves the use of a hojo cord, (sometimes the sageo or tasuke) to restrain or strangle an attacker. These techniques have for the most part faded from use in modern times, but Tokyo police units still train in their use and continue to carry a hojo cord in addition to handcuffs. The very old Takenouchi-ryu is one of the better-recognized systems that continue extensive training in hojo waza. Since the establishment of the Meiji period with the abolishment of the Samurai and the wearing of swords, the ancient tradition of Yagyu Shingan Ryu (Sendai and Edo lines) has focused much towards the jujutsu (Yawara) contained in its syllabus.
Many other legitimate Nihon jujutsu ryu exist but are not considered koryu (ancient traditions). These are called either Gendai Jujutsu or modern jujutsu. Modern jujutsu traditions were founded after or towards the end of the Tokugawa period (1868), when more than 2000 schools (ryu) of jūjutsu existed. Various traditional ryu and ryuha that are commonly thought of as koryu jujutsu are actually gendai jūjutsu. Although modern in formation, very few gendai jujutsu systems have direct historical links to ancient traditions and are incorrectly referred to as traditional martial systems or ryu. Their curriculum reflects an obvious bias towards Edo jūjutsu systems as opposed to the Sengoku jūjutsu systems. The improbability of confronting an armor-clad attacker is the reason for this bias.
Over time, Gendai jujutsu has been embraced by law enforcement officials worldwide and continues to be the foundation for many specialized systems used by police. Perhaps the most famous of these specialized police systems is the Keisatsujutsu (police art) Taiho jutsu (arresting art) system formulated and employed by the Tokyo Police Department.
If a Japanese based martial system is formulated in modern times (after Tokugawa) but is only partially influenced by traditional Nihon jujutsu, it may be correctly referred to as goshin (self defense) jujutsu. Goshin jujutsu is usually formulated outside Japan and may include influences from other martial traditions. Brazilian Jiu-Jitsu, which was developed from judo, but with greater emphasis on ground grappling (ne waza), is an excellent example of Goshin Jujutsu.
JJ techniques have been the basis for many military unarmed combat techniques) for many years.