Buddhism, contrary to Hinduism, is quite a homogenous path to liberation – the Buddha’s Four Noble Truths clearly define it. The difference between Buddhism and Hinduism is that Buddhists do not consider Gods so important as Hindus do; for Buddhists relevant is only the path to liberation or to nirvana the direction of which described Buddha. Buddhism has two basic schools of teaching – Pali Canon Theravada, also called the Southern School (Sri Lanka, Indonesia…) and Mahayana – the Northern School (Tibet, China, Mongolia, Japan…). These two schools have their subschools.
Shingon
Shingon is an esoteric school of Buddhism started by a mysterious monk named Kukai in Japan at about the end of the first millennium (700-800 AD). This form of Buddhism is also known in Japan as Mikkyo (secret path). Mikkyo originated in India and its practice is very similar to the Ganapatyas sect (worshippers of Lord Ganesh who consider Ganesh, contrary to mainstream vaishnavists or shaivists, Supreme God of the universe). Ganapatyas still exist in India, but they are not documented very well, as their practice is secret like that of Shingon. Most information from both teachings has never come out to the public.
Shingon is typical with rituals, magic, with invoking Gods, which you may also notice, for example, by looking at quite very unusual statues of Kantingen (two Ganeshas, a female and male form of the elephant God making love – http://www.freebsd.nfo.sk/esoteric/buddha.htm), which priests in Japan hold from the public eyes and keep in great respect.
Kukai went to China where Hui-Guo, a master of Buddhism, initiated him to Chen-yen or Zhenyan, which is Shingon in Japanese (or Mantrayâna in Sanskrit). Most historians date the presence of Ganesha in Japan back to times when this great monk started his Shingon sect in Japanese Buddhism. The means of worshiping Ganesha, Ganabachi, Vinayaka, or Kankiten hold attributes that make this cult different from all other Buddhist streams.
Kankiten is a real God who exists. There are a few fascinating stories about His appearance in Japan near the temple where He is revered (Kamakura). But He is considered to be very wild, so in Japanese Buddhism He has His female counterpart and that is the reason why statues of Kantingen consist of two elephant-headed Gods embracing themselves. His oldest statue in Japan (13th century) is in Kamakura at the Hookaij-Ji temple. Nanten is the male Ganesha form and Nyoten the female form.