http://www.scns.com/earthen/other/seanachaidh/godjapan.html This is kind of a cool page listing a lot of the Various Gods and Goddess's in Japanese Religions.
Shinto (the Way of the Gods) was the original religion in Japan and had no written literature before the arrival of the Buddhists. All true Japanese mythology comes from this religion. Shinto teaches that every natural thing, human, animate or inanimate, has a spirit in various degrees of vitality and strength.
Shinto is also called the way of the Kami which means "Gods" in Japanese. I find this religion interesting because they had no writings so it makes you wonder Exactly where and from who it originated and how it was passed along through all the ancient villages. Sadly with out keeping literature and a time line I know I will never know the Answer.
Another question I have I know this might not be the correct place for it but none the less it does tie in a little I promise.
It seems the most accient religions in all regions began with more then one "god" or "Goddess" and they where all in some form of ranks depending on what they where the god/goddess of and who the originated from. It makes me wonder how a lot of people just decided one day that the accient Religions where not correct and that there was only one "god". This confuses me because surely the older the religion the closer to truth it must be. I suppose its a question no one really knows the answer to... But its still something to think about.