Please see the horrible exchange rate for CAD cash in Japan.
http://www.narita-airport.or.jp/exchange_e/
Preferred modes of fundings (starting with the lowest cost):
1. No fee USD T/C funded from a USD account
2. No fee CAD T/C
3. CC
4. ATM (Plus and Cirrus)
5. USD cash
6. CAD cash
I have only used 1 ,3, 4, though carry all of the above except #2. Well because in Canada, no Forex CC is hard to find and I don't like the offering. Likewise for ATM.
I also use CC for everything, purchases as little as 500yen.
Chip-and-PIN cards: No problem with Visa/MC everywhere. AMEX rejected by JR ticket machine(MC was ok), accepted at ticketing office - though for different transactions.