Visa and/or Mastercard in Japan?

Someone told me that it somtimes is useful to have both a Visacard and a Mastercard when traveling to Japan, is this true or is it perfectly fine just to bring a (Swedish) Mastercard and some cash...?

I am not sure whether it is more than a rumor, but I heard (and partially experienced myself) that Mastercard is less prone to delays at the cashier due to security checks.

It happens sometimes (especially in electronic stores) that when you want to use a foreign issued credit card, a phone call has to be made for security reasons, which can take 5-15 minutes. I heard and experienced myself that these problems are more likely to happen with Visa than with Mastercard, but I am not sure whether there is any truth behind it.

Generally, both cards are accepted.

Hi, I have both cards and I mostly use visa. BUT even if sometimes they have to make a call many times my cards is rejected. So my advice is to always take cash with you. And forign cards don't work on every ATM, you have to go to a foreign bank like citibank (shinjuku station for exmaple) to take cash.

My us based mastercard pays my softbank bill each month without problems. Also use my mastercard at restaurants, stores, supermarket never had a problem.

foreign credit cards, at least from Canada, work in the ATM of all the 7-11 convenience stores. The Japanese ATM that accept foreign cards often have on their doors or machines pictures of Visa and Mastercard cards (with English script on the cards) above a whole bunch of Japanese cards. Your credit card must of course have the logos of either Cirrus or Plus or Maestro in order to work.