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 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 :)

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