This store is very near the entrance to the Kengun Shopping Street (建軍商店街). Here’s a map:

https://goo.gl/maps/rvNiYxPJBtR2

To see an article about this (I learned about the shop from this article) go to

http://en.rocketnews24.com/2016/03/20/kumamoto-shop-has-automatic-door-control-for-guard-dog-so-he-can-take-pee-break/