Mainly, Buddhism is separated into
2 denominations : Therava¯da and Maha¯ya¯na, the recognition
of the Lord Buddha is different. In Therava¯da Buddhism of Southern
Asia (such as my country, Thailand), Pali scripture has survived and only
one Buddha is recognized, namely, Gautama or Sakyamuni. According to the
Maha¯ya¯na tradition, the type of Buddhism practices in Japan,
China, Korea; Sakyamuni is but one of countless Buddhas presently active.
Maha¯ya¯nists believed in a series of Buddhas --Buddhas from
the cosmic past and also Buddha-to-be, or Bodhisattva (Bosatsu)--who had
deferred their own salvation until the salvation of all mankind. Although
all Buddha are equal in their wisdom and merit, they differ with respect
to the specific vows they made before achieving Buddhahood.
In Japan, Buddhism was first introduced from Korea in 552. The Soga clan argued with others for the acceptance of Buddhism. At last, the Soga clans won, Prince Shoutoku is considered the real founder and first great patron of Buddhism in Japan. After that, Buddhism teachings had begun by six prominent schools introduced by China during the 7th and the early 8th century. And in Nara Period, Buddhism had been established as the state religion by Emperor Shoumu.
At the beginning of Heian Period, the Tendai Sect and Shingon sect were introduced to Japan. They received support principally from the ruling aristocratic class. Later, Zen Buddhism was introduced from China at the beginning of Kamakura Period and was favoured by the dominant military class. The popular sects of Nichiren and Pure Land Buddhism were also organized around the same time.
In Edo period which was under Tokugawa Shogunate, Buddhism and network of temples were used to eradicate Christianity, but Buddhism also came under strict regulatory power of the Shogunate. Then, after Meiji Restoration, the government established Shinto as the national religion and many Buddhist temples were disestablished. Since then, Buddhist organizations have had to struggle for survival and to adjust to the developments of the modern age. Now, since the ending of World War II, many religious groups among the so-called shinkou-shuukyou (New Religion) were organized as lay Buddhist movements. Several of the largest of these groups draw upon Nichiren's teachings and Lotus Sutra.
Or Bukkyou Zuzou, Buddhist deities are divided into four principal groups :