They are based in Tokyo (Nakano). But I believe they print and hand-bind the stories on-demand, so they may not have an inventory ready if you simply stopped by unannounced. So best to contact them about it first.
@maxhodges I just purchased “Ari to Kirigisu” from my ios. I am using an iphone7plus and don’t see any issues on this app. I love how the story, graphics and vocabulary were put together! Great work guys:grin:! Can we see Level 4 graded readers in the near future? Right now, the highest level in store is level3.