There's not really much to say about magic items. They're really up to the DM, and the Dungeon Master's Guide and the tons and tons of books that WotC has produced have lots of magic items that can easily be incorporated into this campaign setting. Sure, you might have to change some of the specific weapons around so that they fit into the Japanese flavor of the game (i.e turning Frost Brand from a +2 frost greatsword into a +2 frost nodachi or something). If you have Oriental Adventures, you can also use the talismans and special items listed in that book. If I ever create any unique magic items, I'll put them here, but as of now I have none.