The most developed place in Japan is Tokyo. Even in the world, Tokyo is a city with relatively high prices. For example, an ordinary lunch is basically 2500 yen, and some high-end buffets are about 4000 yen. If you stay, the price is about the same, and staying for one night is about four thousand yen.
However, Japan's financial system is very mature, and credit cards can be used for food, accommodation and consumption, but some stalls and the like still need to bring cash. Even if the cash runs out, I'm not afraid. The exchange rate of Japanese money changers at airports or roadside is very low. Even 7- 1 1 has a special foreign exchange machine, which is very convenient!