Pocket WiFi Router

Thank you for reading this message.
I have read the article carefully and would like your help if possible.
Answering your question:
1) We are 3 adults, I am my two adult children, they can not be without internet, I do not give value.

2) we will arrive on July 1 - by the 4th we will be in Tokyo,
Day 5 in Nikko and return to Tokyo -
6 - Odawara
7 and 8 - Hiroshima
9 - Fukuoka and Kyoto
9 to 14 Kyoto
15 We'll be back in Germany.

3) in total of 15 days of use

I would be thinking of a Pocket WiFi Router, would it be interesting or what's your opinion? and prices?
softbank or docomo?
Thank you very much.

This should give you what you need:
Some companies are listed farther down the page.

https://prepaidsim.visitjapanplaces.com/wifi

Thank you very much for your prompt response. I believe we will do with Decomo.