I fly to Osaka about once a quarter. I fly out of IAH to NRT, and from NRT to KIX. The travel agent was able to get me on a NW flight from KIX to NRT (this works out great so as not to transfer from the smaller airport in Tokyo to NRT.) When I try to search the flight on NWA their website does not bring up the flight. Does anyone know why that is? I have emailed and called NW but never have gotten any answers. I was thinking that this may be due to some rules in Japan since this is a US carrier flying a domestic route (I think this route started when NW got rid of their direct flight from Detroit or Minn. Incidently, the flight is a 757 and was only 1/4 full. I think this is a codeshare flight with CO (as are the Co flights from IAH top NRT) Of coarse if noone can find the flight no wonder why it is not full.
Incidently, I flew in to NRT yesterday and am spending the week in Tokyo -saw a few Delta 747s (old NWA repaints) - looked pretty cool. I also had an alergy attack while exiting the aircraft, got pulled from the line to have my temperature taken - very polite and was cleared in no time at all (swine flu mitigation)

Your initial hunch is correct, as this is a japanese domestic flight on a US carrier, it cannot be booked "standalone", but only in conjunction with an international flight, such as IAH-NRT or DTW-NRT. The flight shows up on nwa.com if you search, for example, DTW-KIX.

Thanks for the info. Capcity on that flight is low, I am surprized that they still fly the NRT -KIX route.