Dear Yamede,
I agree with what other posters are advising you, i.e. that the JA bank NISA does not seem like a good deal.
The three names- Rakuten, Monex, SBI - mentioned here are probably better bets. If you open a SBI Shinsei account, and use it to
then open a Monex account you can get some extra status etc, same applies probably for Rakuten.
Re: transfer of funds, I used to do the ATM method quite regularly - I am presuming JA bank allow you a certain number of free withdrawals
a month ? Having ATMs that are close together helps from a security viewpoint (e.g. you may find some clustered together in an Aeon etc. )
I used to regularly take out 50 man yen from one ATM, cross the road and put it in another. In the worst case you could
transfer a big amount in one go and pay the 770 yen - but I am with you on not wanting to pay that sort of money to access my own cash.