Originally Posted by ttuna3

OP,
How long of a layover and what time are you arriving and leaving?
Assuming you don't need a visa JAL won't have any issues with getting you an escort to I&C just be prepared for the lines if you don't do the VJW Immigration and Customs before you depart for Japan. This happens all the time so JAL (and ANA) have it down to a science and can advise on the best times to leave and get back to the airport to avoid the worst crowds.
I remember watching a shipmate raising eyebrows when they wanted to go into Tokyo with a 3.5 hour layover during the departure rush hours and politely being told that it wouldn't work because of I&C in and out.