You can live/travel quite cheap in Japan if you know how to. Granted you wont be staying at any 5 star hotels or eating gourmet meals, but it can be done while still having an enjoyable experience. I once paid ￥1900 per night for a hostel in Osaka that had a bar and really friendly managers - every time I go back to Osaka I make sure to make a reservation there :D

Wow! A 3 year plan to stay in Japan for 3 weeks?

I'm just glad you're not planning a 3 year stay. You'd probably be in your 50's by the time you buy that plane ticket. :D

You can find a business hotel in Tokyo for around 5500 yen a night. Toyoko Inn is a popular chain and if you become a member, you can get an even better deal on extended visits.

Of course things could change a lot in 3 years. The yen could be worth something different, the cost of living could go up, the chain could have gone under, etc.

i think its a good idea to start so early. ull be very organised. if u dont plan well enough, then when ur there, u may waste time. its japan! wen i go, im gonna plan super good cuz i want it to be special! thats just my opinion though! i think u should go to the imerial palace. sounds cool to me!! and mt fuji!

I think you are in the right mind set to start saving now, but I wouldnt really start putting too much thought into anything else at this stage - you will just spend 3 years waiting for time to go faster so you can go on your trip!

Trust me, i booked my flights only 6-8 months in advance of my trip and have spent all this time counting down the days.

Also, I dont know what position you are in to save money and how much but since you have three years to save money you could possibly go for longer then 3 weeks or perhaps add a second country onto you itinerary.