Book car 11 or 12 on the Tokaido Shinkansen, car 5 on Tohoku, car 7 on Hokuriku: where the multipurpose room is, how the family car works, and stroller rules.
Should you bring a stroller to Japan or just a carrier? Use a simple age and transport chart, plus train, ryokan, and airport tips, and find 160+ hotels that lend strollers.
Yes, you can buy baby food in Japan: baby stores, large supermarkets and drugstores stock it, convenience stores do not. How much to pack and which hotels serve it.