Spent 10 days in Japan in October , 5 of which were spent in Tokyo . An absolutely amazing place with so much going on . Not too sure I would know what to suggest to do with your 15 year old son as most of the free time we had was spent in the local bars and visiting rappongi ( not for the faint hearted ) but still worth a visit if you keep your wits about you
Stayed at the Hotel New Otani where they filmed the James Bond film " You Only Live Twice " , again quite an experience in itself but perhaps not somewhere I would return to . The bullet trains are incredible and you can set your clock by them , never late . The whole culture is quite amazing and built all around respect for each other . Everything is so organised , and for gods sake , don't jay walk as you will get lynched . Perhaps you need to check out some local tour guides as I think you would need to do quite a bit of research before you left . Oh and I hope you both like fish , raw fish that is , nothing like the sushi we have hear
Overall loved Japan and all it had to offer , but quite a full on place and not perhaps somewhere I would go to relax . If you go hope you both have a great time