Great suggestions up thread. Also worth considering: have your laundry done at a neighbourhood コインランドリー while eating lunch. It can be less stressful than fighting over/babysitting the usual one or two machines at a hotel serving 100+ rooms.

Coin laundries are apparently big business in Japan, so you shouldn't have much trouble finding one these days, especially if you drive. https://www.japantimes.co.jp/news/20...-sign-bursting