+1. No problem using Chase cards (with chip + sig) anywhere in Tokyo and we charge everything we can including 7/11 and Starbucks (need those miles!). However as others have noted credit cards are not accepted everywhere, notably: metro machines and most tourist sights are cash only and some of the cheaper restaurants (though happy to pay cash there given the savings)
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We had no difficulty using Chase ATM and Fidelity debit cards at 7/11 ATMs which are easy to find in Tokyo - there are even some standalone 7/11 ATMs in metro stations (though I didn't use those as I am neurotic about skimmers). Also used Citi ATM card to get cash at Citibank (though not preferred method due to 3% forex).
We are burning through about $100 cash per day which is high for us and an indication of how many places do not accept cash.
Update: As noted below 7/11s are everywhere in Tokyo, Kyoto and Osaka and easy to get cash with ATM cards issued in USA. Also my Chase cards have been used everywhere in Tokyo, Kyoto, Osaka - restaurants, dept stores, Lawsons, etc. with no problems. Can't speak to useless CSP as I don't have one or want one (but that's another debate for another forum).