How much money is enough for 2 person's expenses in Japan for 3 weeks?

Question:

Me and my partner are planning for a 3 week vacation.
Places that we would be covering will mostly be Tokyo & Osaka.
At the moment, we are deciding to bring about Singapore dollars $5000 (Approx. 302014 Yen)
Expenses would cover transportation,food...
Accomodation has already been covered. Disneyland/Sea's ticket has also already been bought.
What's left is probably the ticket for Universal Studio in Osaka.
Could someone please advise, or share their experiences with us?

Thank you.

Answer:

I think 300000 yen is enough for 2 people for three weeks considering your accomodation has already been covered. So, don't worry at all.
All the best!!