On my last trip to Japan, I attempted to reset my body clock for about a week prior to departure (going to bed earlier and earlier each day, and getting up earlier). The night before departure, I pulled an all-nighter. I got onto the plane at ORD, at a light dinner, popped a sleeping pill & went right to sleep. I was in first, so I was able to sleep pretty comfortably for about 6 hours. Once we arrived in Tokyo (about 3 pm), we stayed up until about midnight then went to sleep. We still had the inevitable 4 am wakeup, but the next day fell right asleep at the proper time & slept through the night.