The Keyboard Speciality shop you linked is great. It is always surprisingly crowded for such a niche topic. The have good test boards with different key switches.

Note that in the area are quite a few other good shops. Tsukumo has various hardware across many floors and also keyboards, in b1 they also have a razer store. Then there is a shop across the street Galleria or something, more targeting esports, if you are into that.

I've been there, but it definitely felt like more of an enthusiast experience. Someone who's just looking into getting their first mechanical keyboard would do better at a larger shop stocked with cheaper keyboards and a greater variety of common switch types.

That being said, the shop is located in a surprisingly quiet area, surrounded by other small enthusiast shops. I especially liked "High Beam" a few stores down, which specialises in handheld PCs.

They have a switch tester board where you can press individual keys and you can see which switch you just pressed on the screen

I went there last time I was sent on a business trip to Japan! It’s a fun little shop. Wasn’t so crowded at the end of October :)