Well, it's got about the same surface area as New Mexico.<p>There's a lot of coastline, so if you accept one-way communication, we could try to encourage citizens to throw message-in-a-bottle into the Sea of Japan or the Yellow Sea, and then try to catch them later.<p>You could teach citizens to put a white or a black 1 square meter tile on their roof each day, and use that as a low bit-rate message... Using satellites.<p>Sat phones occur to me.