Many small restaurants, temples, and tiny shops only accept cash. ATMs at 7-Eleven, Family Mart, and Japan Post accept foreign cards 24/7.
Carry 10,000–20,000 yen in cash daily. Coins are heavy but useful for small shrines, lockers, and bus rides.
IC cards (Suica/Pasmo) handle most micro-transactions, so cash is mainly for restaurants and shops.