Will add more as I think of it. True! The SUICA card system for paying for travel - and some convenience store items - in Japan via the wallet app on your phone is pretty impressive Until it doesn’t work on your wife’s phone and nobody can figure out why Despite SUICA and QR Codes, be prepared to carry multiple small pieces of paper that represent - separately - your train reservation, your actual train ticket, your seat assignment, and your receipt, and they may be different sizes, and only one of them goes in the machine.