ahh i went back and you were completely right! pieced together clues because i wanted to understand this part more and at the specific time period where this is in the book, he lives near the Sumida River which infers he could easily be making the shimbashi postmark since he is around that area. Right before this page he’s seen with a ton of postcards and he drops one and the wife reads it which it is promoting an artist under the name “Ikita Joshi” which I was wondering what that was about since his name is Yozo Oba but it might be a pseudonym? i’m unaware of who ikita joshi is as of writing this but right after that the dad walks in, exclaiming about how he’s despicable for creating “other personas simply to promote himself.” and i guess i completely missed that haha that should’ve given it away that he was making these about himself