Microsoft has revealed on the Japanese version of Inside Xbox that it is planning to announce something in the third week of February, which is next week. Microsoft wouldn't comment on the size or the announcement of what the announcement will be about. Rumors are now spreading about multiple things.
It could be that Microsoft is announcing a new bundle for Japan, or a release date for a future game or maybe even a official price cut. It could also be something way smaller than that, considering Microsoft is celebrating the Xbox's 6th birthday in Japan next week. We will just have to wait and see what Microsoft has in store for us and the Japanese gamers.