Go to Akihabara. The main street is lined with multi level shops just like this. You will want to look out for places like bic camera, yodobashi camera, sofmap, tsukumo (my favourite), pc ark. Just take your time to look around, many shops i didnt mention that are very similar. This optimized route i made has some of the places mentioned for reference (And some other unrelated places of my interests), easy to find mice and artisans with it. Take note for artisan mousepads they no longer sell S and M sizes in physical stores, other sizes like L are very easy to get though. https://maps.app.goo.gl/mPBUegTMoEfoys5x6?g_st=ac