i went last Easter. Nara's cool but the deer become real annoying real fast.
you are here, so i can surmise your tastes

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In Tokyo, Osaka and Kyoto, look for a shop called "Melonbooks"; the Osaka and Kyoto ones are simple doujin shops, where you gotta browse trough shelves of smut.
The Tokyo one is a giant tower, 7 or 8 floors tall. enter and go to the counter on the right. prepare a text file with a list of doujin names (in japanese) and show it to the nice ladies that work there. they'll enter an elevator an fetch them for you in a couple of minutes.