Good to Know
Wall sockets are US style, 110V.
No need to tip anywhere, anytime. Makes everything so much easier.
Stand to the left when riding escalators. This goes for pretty much all of Japan with the exception of Osaka.
When communicating, the Japanese use ✕ for no (indicate with your index fingers crossed) and ◯ for yes (indicate using 👌). This along with the insane politeness of most Japanese people will get you a very long way when trying to bridge those language barriers.
Credit cards are less likely to be accepted the further you get from the major cities. And it's harder to find ATMs accepting foreign credit cards, so you'll want to plan your cash logistics accordingly.
Bring cash. Getting hold of it while in Japan might require more logistics than you think, especially when venturing outside major urban areas. And quite a few places and taxis don't do credit cards.
Order a rental pocket wifi device to be sent to your hotel, or pick it up at the airport. If you don't have cheap roaming, do it.