Luggage storage for Shikoku pilgrimage

Hi,

I'm planning to do the Shikoku pilgrimage. I'm calculating with a duration of about 6-8 weeks. Meanwhile I'd like to leave my suitcase either in Tokyo or Kochi (Shikoku). The best option I found yet is located in a Tokyo station, where you can leave luggage up to a month. Do you have any recommendations where it is possible to leave it up to two months?

by MiatDiGadse