which one has the better exchange rate

which one has the better exchange rate, is it licensed money changer or automated money changer inside some hotels or post office? i want to exchange from USD to JPY.
thanks in advance for your help.

If you use the search function with terms money exchange etc, you'll find heaps of answers. And the answers are all different due to many various factors effecting the individual.

All you can do is your own research asking your own bank first, then move on to other avenues to find the best price.

licensed money changer = leagalised theft.
automated money changer inside some hotels = poor rate
Auto changer at airport (like Narita) = actually better rate than the bank it is next to when I used it last.
Bank = proper way to exchange money - same rates across the country.

Skip bringing cash and just use your ATM card at a Japanese post office or ATM. There are tens of thousands across the country, and especially for the 7-11 ATMs they are open virtually 24/7.
http://www.jp-bank.japanpost.jp/en/ias/en_ias_index.html
http://www.sevenbank.co.jp/intlcard/card2.html

If you do plan to use your ATM card in Japan, make sure your bank knows about it first so they don't suspect fraudulent usage and freeze your account.

I have heard a few people recommend Daikokuya for buying yen with cash but I have never done it and would research it first.