An illustration of the "ultra free" market in Japan, is the insane amount of ways to pay at the cashier. It seems every financial group thought they could do better than the other, and for some reason I don't understand, they didn't eat each other, they just coexist.
The main categories are: bank card, payment apps connected to bank account, transportation cards, electronic money. They may work through card reader, no-contact, bar code scan or QR code scan. For the last two, you are either scanned or you have to scan them.
Also, Japan loves "points". If you know the cashback system, where you get something like 1% of your bill back, in Japan they usually get points back, which are of course limited to shops accepting those points. So on top of payment methods you also have a dozen of points system, either specific to the shop brand or from a different company that may have agreements with different merchants.
Despite that, cash remains essential, it's very common to end up in a restaurant that only accepts cash, even the convenience of paying your house bills at the konbini requires cash.
