[MMM]

I wouldn't recommend it for a couple reasons. Besides the long plane ride, you are facing a lot of challenges that might dissappear if you wait a few years.

Japanese children are taught from birth not to run into the streets. Sidewalks are a luxury in Japan, so it isn't uncommon to be walking on suburban streets with cars, motorcycles, bicycles and scooters whizzing by. only inches away. Of course in the major cities there are sidewalks.

Parks tend to be just dirt, and aren't always very well kept.

I think it would be a lot of work and you would miss out on so much and your children aren't even old enough to remember the trip.