Challenge: Islamic Japan

With a POD of 650. Bonus points for becoming the dominant religion. Double bonus if it becomes the state religion. Triple bonus for a TL.
 
Not very difficult I think. I'm fairly certain the Japanese had raids against some of the Muslim parts of Southeast Asia (although i could be wrong. However, they probably got very close), so we know there was contact. So all we need is for one captive to be a devout and charismatic man, or perhaps a trader and they slowly spread Islam through the populace. Catholicism spread fairly fast in the 1600s, and without a foreign power backing it, the spread will be probably be slower, but less threatening to the local power. The big breakthrough happens when an important daimyo converts, after that we just have to make him successful.

Considering the history of Religion in Japan (best summed up in the phrase, "A Japanese is born Shinto, married Christian, and buried Buddhist) I think we can expect an extremely 'liberal' version of Islam, with a lot of syncretic elements from Shinto, Buddhism, Confucianism and whatever else happens to be on hand. A really interesting idea actually. I'd have a better idea If I knew more about Indonesian Islam, but unfortunately I don't. Anyone care to contribute?
 
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