Just finished it. Very enjoyable and a great story (read it in two sittings.) If you’re interested, a few comments.
1. Started too slow and ended too fast.
2. The prose could be enlivened and tightened up a bit.
3. It kind of missed the banking ethos of that era, but that probably made it a better story.
4. It didn’t really feel like the Tokyo I knew at the time. Could be a generational thing, but I feel like it lacked the intense sensual elements that were everywhere present in Tokyo. (Nailed it though on your Moti Butter Chicken description.)
Finally, thanks! A wonderful gift, which I really enjoyed.