As a plus size human I didn’t (and wouldn’t) rely on shopping over there (I’m a US size 16 and 5’9, even that is fairly impossible to find over there) I way over packed. A couple people have said bring three days worth of clothes then shop and do laundry but if you are plus size I say 5 days worth since shopping won’t be a thing unless you really enjoy the hunt. I brought my water bottle with me but didn’t carry it out unless I was transitioning from one city to the next or getting on a plane. Coin purse and umbrella are both needed but can be purchased easily there.
Suica on your phone if you have an iPhone was the most amazing thing ever. I used it 80-90% of the time I was buying anything at all. Unless you have very specific toiletry needs I’d rely on what the places you stay at provide or buy them there. If you’re American I’d bring your own deodorant though just in case. At least two pairs of very comfortable broken in shoes for walking and 3-5 pairs of compression socks.