The very first Buddhism to arrive in Japan was Theravada (Sanskrit for "the lesser vehicle"); called Hinayana ("not Mahayana") by the Mahayana Buddhists. This is a collection of sects which, in many ways, are closest to the original teachings of the historical Buddha. They utilize the Pali Canon, the oldest Buddhist texts - written in the Buddha's language, and stress study of his direct teachings and actions in life. Hinayana Buddhism generally asserts that to achieve enlightenment is very difficult - most students in this life will be lucky if they gain enough merit to reincarnate in the next life with better karma and thereby be one step closer to fulfilling Nirvana. Thus, Hinayana Buddhism stresses monastic life and feels the individual needs to look after his or her own development. This is not selfishness, it is merely a statement of realism: it is arrogant to think that you can help anyone else when you can barely help yourself. This attitude, however, does not in any way prevent students from practicing compassion towards other beings.
Most of the sects in Japan with which we are familiar grew from the Mahayana school (Sanskrit. "Great Vehicle"). Mahayana developed in India during the first century CE It is called the Great Vehicle because of its all-inclusive approach to enlightenment, as embodied in the Bodhisattva ideal, and the desire to liberate all beings. In other words, the student's goal is enlightenment, but more so, to become like a Bodhisattva ñ an enlightened being who uses his strength to assist other less fortunate beings. (example: The Chinese deity of mercy, Kuan Yin is considered to be a Bodhisattva as are Hotei and Japan's own Jizo who regularly enters hell to rescue lost souls) In China, Mahayana Buddhism flourished and took on many forms. Mahayana Buddhism entered Japan around the sixth century CE with the rapid assimilation of Chinese culture in general.
Finally, there is Vajrayana (Sanskrit. "Diamond Vehicle"). Vajrayana developed out of the Mahayana teachings in northwest India around 500 CE and spread to Tibet, China and Japan; it involves esoteric visualizations, rituals, and mantras which can only be learned by study with a master. It is also known as Tantric Buddhism due to the use of tantras, or sacred texts. Vajrayana incorporates several deities. Intellectually, these are considered largely symbolic of states of being, or power originating from enlightenment, but may be worshipped as real by the masses.
The "Old Sects"
Tendai: The ninth-century founder of Tendai is known as Dengyo Daishi (767-822), a posthumous title meaning "great teacher and transmitter of the Dharma". Daishi was originally a Hinayana Buddhist priest in the old capital of Nara. Around 800 CE, he journeyed to China to study Mahayana Buddhism with the sect of T'ien t'ai (J: Tendai) Mountain. This consisted exclusively of Lotus Sutra teachings which were the underpinning of the classic writings of the patriarch Chih-i.
Upon returning to Japan, Daishi left Nara and established a small temple called Ichijo Shiken-In near the top of the then-sparsely populated Mt. Hiei, just northeast of Kyoto (then Heiankyo). Here he remained confined for twelve years of practice. He founded a new form of study and practice based on the Lotus Sutra teachings along with advanced meditative theories. Later, esoteric practices (visualizations, rituals, and mantras) were also added. These are sometimes called "Taimitsu" or "Mikkyo" (secret teaching). and are similar to the esoteric practices of Shingon.
Both Nichiren and Rinzai are descendants of Tendai; most of their founders (including Daishi himself) having been members of the monasteries on Mt. Hiei. Jodo, or Pure Land Buddhism is also closely associated with Tendai. See: www.tendai-lotus.org.
Shingon: Shingon is more or less a form of Vajrayana Buddhism. Established by Kobo Daishi (Kukai) at the beginning of the Heian period (9th century), this school is known for its stress on Mikkyo practices and blends many doctrines, philosophies, deities, religious rituals, and meditation techniques from a wide variety of sources.
The teachings of Shingon are based on the Mah'vairocana Sutra (J: Dainichi-kyo) and the Vajrasekhara sutra (J: Kongocho-kyo). These sutras were probably written during the last half of the seventh century in India. They contain the first systematic presentation of Mikkyo doctrine. The center of Shingon was the monastery complex on Mt. Koya. The famous Yamabushi are related to the Shingon sect. See www.shingon.org.
The "Young Sects"
Some Background and an explanation of Sohei
In the early Kamakura period, Buddhism in Japan was rife with corruption. The great monasteries on Mt. Hiei, Mt. Koya and in Nara were quite materialistic and involved in politics, land disputes, and even warfare. Their branch temples dotted the Empire and allowed them to exercise considerable power. (by most accounts, the Tendai of Mt. Hiei seem to have been the worst)
One good example of monastery corruption is the rise of the Sohei. Sohei began to appear in the Heian era. The term means "novice" and came to be a catch-all term for warrior monks attached to a given monastery ñ most notably those on Mt. Hiei. Most Sohei were poor Buddhists. Often recruited from peasants living around the temples, they were essentially enforcers: brash, uneducated, poor practitioner of the Dharma who ate meat, brawled and knew women. (not a bad lifestyle in the eyes of many a SCAdian, neh?). A classic maneuver of the monasteries was to send Sohei down into the capital whenever they were upset about something. The monks would carry ceremonial floats bearing important images from the temple halls. After picking a fight, or having an "accident" with people in the streets, the monks would become incensed by the disrespect the people, police, government and even the Emperor himself displayed for the Law of Buddha. Protests outside the gates of the imperial palace could turn into ugly riots. Later on, during and after the Genpei War, the Sohei were assigned to support samurai armies whose commanders held the monastery's favor or to whom they owed a favor. To varying degrees, this sort of thing went on right up until Oda Nobunaga thrashed the monasteries of Mt. Hiei and forcibly disbanded the Sohei.
In the popular culture, people referred to the age of Mappo, the "latter days of the dharma". This expression, popular from late Heian into Kamakura, implied that the world was in a state of decline. There were thought to be several ages of the Buddha's teachings, and this was the last before the end of the world. This pessimism only served to fuel social and spiritual anxiety. Certainly, on a political level it may have been true as the Heian court saw it's downfall and military government took over.
As a reaction to the lack of sincere spirituality, several monks began to explore other methods and schools. Seeking to move away from the esoteric practices, which often involved magical rites, deities, etc, many embraced Zen: the word meaning meditation.
Jodo: The "Pure Land" devotional form of Buddhism advocated surrender to a Bodhisattva as a means to be reborn in his Pure Land (a realm free from suffering) from which it is easier to attain nirvana. In most of the flavors in Japan, this meant Amitabha; Amida Buddha and his "western paradise". Adherents believed that all that was required was for the believer to call the name of Amida with pure sincerity ñ usually upon one's deathbed. ("Namu Amida Butsu... Namu Amida Butsu...") Amida would then descend out of the western sky riding on a white elephant in a swirl of pink clouds and personally escort the dying person's soul to the pure land. Jodo stresses compassion and it's priests regularly perform various rites for their parishioners, often visiting them at home. While Jodo had been in evidence for centuries in Japan, it did not gain great popularity until the Kamakura era. If Tendai is Catholicism, then Jodo is Protestantism, in a certain simplistic metaphor. A popular Kamakura expression said, "Shingon is for the Imperial court. Tendai is for the nobles. Zen is for the samurai and Jodo for the masses."
Nichiren: Nichiren (1222-1282) was a monk trained on Mt. Hiei who believed in the supreme perfection of the Lotus Sutra. Disenchanted with the highly esoteric teachings and practices of Tendai, he advocated the devout recitation of "Namu myoho renge kyo," the title of the sutra, in order to attain instantaneous enlightenment. Nichiren taught his doctrine to the masses who, intimidated by Tendai and Shingon complexities, were open to newer, more direct paths to salvation. His followers would later claim that he was the reincarnation of the cosmic Buddha. The Nichiren sect may be seen as a sort of bridge between the purely meditative technique of Zen sects and the devotional technique of Jodo. It can almost be considered esoteric in that its rituals and practices are somewhat obscure.
Zen Sects: "Zen" is the Japanese pronunciation of the Chinese word Ch'an, which in turn is a rendition of the Sanskrit term dhyana, meaning "meditation". An Indian monk named Bodhidharma started the Ch'an school of Chinese Buddhism when he came to China in 520 C.E.. Zen flourished during the T'ang dynasty led by such powerful figures as Chih-i, Hui-neng and Lin-chi (who started the sect now known as Rinzai in Japan). Zen became the most popular form of Buddhism in Japan during the Kamakura period when it was adopted by the samurai. The school stresses the importance of the enlightenment experience and the futility of rational thought, intellectual study and religious ritual in attaining this; a central element of Zen is zazen, a meditative practice which seeks to free the mind of all thought and conceptualization. For doctrine, zen sects tend to focus on the Lotus sutra as their primary source. Just as important are the teachings and sayings of previous zen masters (especially of a sect's own lineage). One example is the platform sutra or "dusting the mirror" sutra of the sixth great patriarch Hui-neng (638-713) which discusses the concept of sudden enlightenment. Zen was also heavily influenced by Taoism as it developed in China.
Rinzai: One of the two major schools of Zen Buddhism, Rinzai was founded by the Chinese master Lin-chi I-hsuan (Japanese; Rinzai Gigen) and brought to Japan by Eisai Zenji at the end of the twelfth century; it stresses koan Zen as the means to attain enlightenment. A koan is a paradoxical riddle or statement that is used to force the mind to abandon logic and dualistic thought. "What is the sound of one hand clapping?"
Soto: (Chinese. Ts'ao-tung) is the other major school of Zen Buddhism. It was brought to Japan by Dogen (1200-1253) in the thirteenth century; it emphasizes simple zazen, or sitting meditation, as the central practice in order to attain enlightenment.
The "Exotic Sects"
Yamabushi: Literally translated as "mountain warrior" and is the term used to describe members of the Shugendo sect; a branch of Shingon founded (according to legend) by En-no-Gyoja in the seventh-century. Shugendo stresses physical endurance and trial as a means to realizing personal strength, and ultimately, enlightenment. One could almost call this sect Xtreem Shingon!. It's practitioners spent most of their time wandering the mountains of Japan visiting holy sites; Buddhist as well as Shinto. Their most extreme rituals include walking across beds of red-hot coals, chanting while sitting under ice-cold waterfalls and hanging from their feet from the edges of cliffs. Not surprisingly, these monks gained a powerful reputation for magical abilities. In art and folklore, they are closely connected to the infamous tengu (crow-men) who seem to love to taunt, irritate and impersonate Yamabushi. Yamabushi are also associated with shinobi (ninja) on the premise that shinobi tactics were born in the mountains these men inhabited. The sect still survives today.
Fuke: Commonly known as the Komuso ("monks of emptiness"), Fuke is a Zen offshoot said to have been founded by Shinchi Kakushin (1207-1298) who was a noted early Zen advocate and multi-talented monk. The Komuso's Zen centers upon mastery of the shakuhachi; a flute made from the base of a bamboo stalk. (note: the shakuhachi is a traditional monk's instrument imported from China. In the Edo period, it became increasingly popular with lay-musicians as well.) Fuke monks stressed pilgrimage and would wander around the Empire playing their flutes as they walked - a very physical form of meditation. I am unsure what formed the foundation of their doctrine, but then, it is possible they did not have much of a doctrine to begin with. Most Komuso were lay-practitioners, not truly ordained monastics. Towards the end of the Momoyama period and into the Edo era, their ranks included many ronin. As a result, the sect gained a bad reputation as ruffians and perhaps thieves used its uniform as an easy dodge from the authorities. Popular legend (and several grade-B movies) says that Tokugawa bakufu ninja spies often disguised themselves as Komuso. This is unverified. See www.komuso.com (mostly post-period information)
Senin: Not truly a sect at all, I include this group here in case someone would find it interesting. Senin is a general term for the Taoist hermits of Japan, particularly of the Nara and Heian periods. Another cultural import from China, Taoist philosophy and mysticism was all the rage in these early times. Taoist sorcerers performed exorcisms for the Imperial court and Taoist geomancers arranged the layouts of gardens, homes and government offices. (Feng Shui) Meanwhile, the Senin, in true Taoist fashion, chose to live apart from the ailing world of civilization and return to nature. Wandering in the mountains and living in caves, Senin meditated on the Tao and, according to legend, amassed great magical powers as a result of their purity and close communion with Nature and the kami (nature spirits). In many respects, the Senin were the precursors of the Yamabushi and various Zen hermits.