The best Japanese food in Amsterdam is probably to be found at the Yamazato restaurant which is in the Okura Hotel, i think it has a Michelin star but is extremely pricey. Nearby is another good restaurant called Kaiko, i haven't yet eaten in either of these.
For some strange reason i developed an eating disorder when stoned in Amsterdam and Japanese food is about all i can eat (except midnight munchies of course).
I always eat at these two restaurant and both are excellent.
http://www.zushi.nl/
it's around the corner from Rembrandtplein, very central, on a canal, light and airy, not pricey, and the sushi travels around on a conveyor belt and you just grab what you want and they total up the different coloured plates at the end for your bill. The deserts here is good too
http://www.japaninn.nl/
it's around the corner from Leidesplein, it's very cosy, great service, wonderful food, excellent menu
