Some more potentially useful links on luggage storage:
https://livejapan.com/en/article-a0001461/
Ueno has a TON of lockers in various spots around the station complex:
https://www.uenostation.com/lockers-...orage-in-ueno/
Tokyo also has a few manned "cloak" desks:
Coin Lockers/Baggage Storage at Tokyo Station?Tokyo Station City