Ooo Japan my favourite place.
I was there last autumn, the yen is very weak against the pound, almost half the price of what we have experienced in past Japan trips.
if you a staying in central cities, Monzo card is fine. Cash is only really needed for the outskirts of town and if you go markets. If you are a fan of gachapon machines then you need coins for that. We would just withdraw money from the local combini (withdraw in yen) when we needed.
the suica or pasmo card will need to be first purchased with cash but if you download the suica app you can add it to your Apple wallet and then just top up on your phone using your card. I’m not an android user but I imagine it’s similar. Travel is so cheap. Under 5s on local trains travel for free.
I brought Shinkansen tickets in advance using klook.com but to be honest I would recommend that at the moment because the yen is so weak, we would have saved ourselves around £60 buying on the day.
if you have tattoos, they will need to be covered. Always take a plastic bag for your rubbish, Japan is very clean but you don’t see bins on the street. Try to learn some key phrases, you will benefit from having a basic understanding of the language, most things in larger cities do have English translation but the further out you go, the less you see.
Japanese people don’t cause one another a nuisance, so on trains you are quiet, you don’t take up lots of space, you move to one side when someone approaches, and if you go to a traditional restaurant you will be asked to remove your shoes, so always have clean not holey socks.
do not tip.
If you end up buying lots of souvenirs, go to Don Quixote (or donkey) to get a large suitcase.
I wouldn’t bother taking toiletries, just buy when you are there because it’s pence. An umbrella and rain coat is essential. Weather is usually quite warm compared to UK but they are prone to a torrential downpour. The upside of this it that everywhere is beautiful and green. When we were there bright blue hydrangeas lined the street.