The practice of martial arts in Japan, known as budo in Japanese--which also is the same word for "grape"--would require a book to describe in full. To simplify, budo can be divided into two categories: red and white (perhaps my bad grape pun should best end here). There are two schools of budo: koryu or kobudo, which are the older disciplines, and gendai budo, which are relatively more modern disciplines.
Within the kobudo group you will often encounter the word ryu or jutsu (meaning "the art") attached to the name. There are hundreds of specific old forms, many of which have been lost over the centuries, which all focus on specific techniques or weapons training. Many of the techniques were hard, real combat techniques intended to kill as much as disable an opponent. Within this group you will find some of the most familiar: sumo, ju-jutsu, ken-jutsu, naginata-jutsu, ninjutsu, batto-jutsu, iai-jutsu and so-jutsu. One of the most familiar terms for people in the west is ju-jutsu, which can be described as the art of using indirect force to disable a often armed opponent. There are hundreds of specific schools, one of which is aiki-jutsu, from which modern aikido is derived. Ken-jutsu, is the older form of swordsmanship in Japan, using a bamboo or wooden bokken in place of the familiar, yet deadly, katana (samurai sword). Naginata-jutsu is lesser known in the west, but is the art of using the naginata, a spear-like weapon consisting of a long pole with the equivalent of a razor sharp katana on the end. Naginata-jutsu has been more popular with women since the early 1900s--along with kyudo or Japanese archery. Batto-jutsu and iai-jutsu focus primarily with the technique of drawing, quickly wielding, and returning the razor sharp katana to its scabbard without losing a finger, while iai-jutsu is more detailed, self-disciplined and elaborate, and more resembles the detailed aesthetics of sado (tea-ceremony). Nin-jutsu, the art of the ninja, is perhaps the most contentious, because most of its techniques have probably been lost, largely because ninja, hiding away in a secret mountainous location in the area of Iga in what is now Mie Prefecture, intentionally practiced their unique form of budo in secret. Though, it isn't officially recognized in Japan, many of its modern adherents (primarily in the West) suggest it is more or less authentic, but the real answer will remain, well, a secret.
Within the modern school of gendai budo you will find even more familiar terms: kendo, judo, aikido, kyudo and karate. In this category, do meaning "the way" is more of an art form than combat. Karate, which is very popular in the West, is actually from the remote sub-tropical island of Okinawa, and is a modern fusion of local Okinawan and Chinese martial arts. Judo, a modern and more specific form of ju-jutsu, is far more popular in mainland Japan, and is usually taught to some extent in high school, along with kendo ("the way of the sword" or Japanese fencing). Amongst my wife and I, aikido is our personal favorite. It is "the way of meeting one's 'ki' (chi in Chinese) or inner energy". Similar to judo, it uses techniques, basic physics really, that primarily use an opponent's own energy and momentum to disarm or disable their attacker. Kyudo, Japanese archery, is a heavily-detailed discipline that was (and somewhat still is) a favorite of Zen Buddhist practitioners for achieving shin no mushin, ("mind without mind"), an intuitive flow of practice that is free of preconceived notions, ego, fear, and other conflicting or contradicting distractions.
If things weren't complicated enough, and I really am making things simple, you can add a variety of interesting weapons and their own schools of use: the bo, jo, han-bo, tan-jo, yawara (a hand sized stick), tonfa (a baton with a side handle that is used by modern law enforcement), nunchaku (mispronounced "numchucks"), sai, kama (a sickle), eku (which resembles a boat oar), tessen (an inconspicuous looking, but all-metal hand-held fan), and shuriken (throwing stars). Probably the most familiar are the bo (which mysteriously means "stick" in Japanese), which is a long staff, and jo, a shorter staff the length of a walking stick. The han-bo, almost exactly half the size of a bo, and tan-bo, about half the length of the han-bo are much lesser known. Less than half the length of tan-bo are hashi, which are used for battling over that last piece of sashimi, and are what people in the West call "chop-sticks". Jo-jutsu, the way of the jo-staff, is the most common discipline based upon a single weapon in mainland Japan, and is often used by practitioners of aikido. The jo, which can be employed with other martial art forms, is probably one of the most versatile martial arts weapons. Curiously, the nunchaku, despite being immensely popular in the West, is probably one of the least versatile, and has no known original kata (choreographed exercises of movement), and it's origin remains controversial. It provides an interesting advantage given that it can strike at unpredictable angles, but can also strike it's practitioner equally well at the same unpredictable angles. Likewise, the shuriken, "throwing star", is well known, but served as a distraction more than a lethal weapon. Often dipped in poison, a ninja would fling them at his assailant, in a last ditch effort, shortly before his own demise.
The recently purchased tan-bo, featured in the photo above, look like little more than taiko (Japanese drum) sticks, but are one my favorites. Baton sized, they can be used like a jo, but can also be wielded in pairs, can be dropped into a protective forearm defense similar to the tonfa, and have their own increasingly rare school of tanbo-jutsu, which uses a variety of heavily coordinated strikes, intricate blocks and joint locks.
Within the kobudo group you will often encounter the word ryu or jutsu (meaning "the art") attached to the name. There are hundreds of specific old forms, many of which have been lost over the centuries, which all focus on specific techniques or weapons training. Many of the techniques were hard, real combat techniques intended to kill as much as disable an opponent. Within this group you will find some of the most familiar: sumo, ju-jutsu, ken-jutsu, naginata-jutsu, ninjutsu, batto-jutsu, iai-jutsu and so-jutsu. One of the most familiar terms for people in the west is ju-jutsu, which can be described as the art of using indirect force to disable a often armed opponent. There are hundreds of specific schools, one of which is aiki-jutsu, from which modern aikido is derived. Ken-jutsu, is the older form of swordsmanship in Japan, using a bamboo or wooden bokken in place of the familiar, yet deadly, katana (samurai sword). Naginata-jutsu is lesser known in the west, but is the art of using the naginata, a spear-like weapon consisting of a long pole with the equivalent of a razor sharp katana on the end. Naginata-jutsu has been more popular with women since the early 1900s--along with kyudo or Japanese archery. Batto-jutsu and iai-jutsu focus primarily with the technique of drawing, quickly wielding, and returning the razor sharp katana to its scabbard without losing a finger, while iai-jutsu is more detailed, self-disciplined and elaborate, and more resembles the detailed aesthetics of sado (tea-ceremony). Nin-jutsu, the art of the ninja, is perhaps the most contentious, because most of its techniques have probably been lost, largely because ninja, hiding away in a secret mountainous location in the area of Iga in what is now Mie Prefecture, intentionally practiced their unique form of budo in secret. Though, it isn't officially recognized in Japan, many of its modern adherents (primarily in the West) suggest it is more or less authentic, but the real answer will remain, well, a secret.
Within the modern school of gendai budo you will find even more familiar terms: kendo, judo, aikido, kyudo and karate. In this category, do meaning "the way" is more of an art form than combat. Karate, which is very popular in the West, is actually from the remote sub-tropical island of Okinawa, and is a modern fusion of local Okinawan and Chinese martial arts. Judo, a modern and more specific form of ju-jutsu, is far more popular in mainland Japan, and is usually taught to some extent in high school, along with kendo ("the way of the sword" or Japanese fencing). Amongst my wife and I, aikido is our personal favorite. It is "the way of meeting one's 'ki' (chi in Chinese) or inner energy". Similar to judo, it uses techniques, basic physics really, that primarily use an opponent's own energy and momentum to disarm or disable their attacker. Kyudo, Japanese archery, is a heavily-detailed discipline that was (and somewhat still is) a favorite of Zen Buddhist practitioners for achieving shin no mushin, ("mind without mind"), an intuitive flow of practice that is free of preconceived notions, ego, fear, and other conflicting or contradicting distractions.
If things weren't complicated enough, and I really am making things simple, you can add a variety of interesting weapons and their own schools of use: the bo, jo, han-bo, tan-jo, yawara (a hand sized stick), tonfa (a baton with a side handle that is used by modern law enforcement), nunchaku (mispronounced "numchucks"), sai, kama (a sickle), eku (which resembles a boat oar), tessen (an inconspicuous looking, but all-metal hand-held fan), and shuriken (throwing stars). Probably the most familiar are the bo (which mysteriously means "stick" in Japanese), which is a long staff, and jo, a shorter staff the length of a walking stick. The han-bo, almost exactly half the size of a bo, and tan-bo, about half the length of the han-bo are much lesser known. Less than half the length of tan-bo are hashi, which are used for battling over that last piece of sashimi, and are what people in the West call "chop-sticks". Jo-jutsu, the way of the jo-staff, is the most common discipline based upon a single weapon in mainland Japan, and is often used by practitioners of aikido. The jo, which can be employed with other martial art forms, is probably one of the most versatile martial arts weapons. Curiously, the nunchaku, despite being immensely popular in the West, is probably one of the least versatile, and has no known original kata (choreographed exercises of movement), and it's origin remains controversial. It provides an interesting advantage given that it can strike at unpredictable angles, but can also strike it's practitioner equally well at the same unpredictable angles. Likewise, the shuriken, "throwing star", is well known, but served as a distraction more than a lethal weapon. Often dipped in poison, a ninja would fling them at his assailant, in a last ditch effort, shortly before his own demise.
The recently purchased tan-bo, featured in the photo above, look like little more than taiko (Japanese drum) sticks, but are one my favorites. Baton sized, they can be used like a jo, but can also be wielded in pairs, can be dropped into a protective forearm defense similar to the tonfa, and have their own increasingly rare school of tanbo-jutsu, which uses a variety of heavily coordinated strikes, intricate blocks and joint locks.