Nicht aus eigener Anschauung, sondern aus dem Talkbass-Forum "Going to Japan":
Are you going to Tokyo? If so, I highly recommend going to the Ochanomizu area(御茶ノ水). You can get there via the JR Line or the subway. There are bunch of stores down the street. I highly recommend ESP’s store BIG BOSS. Some of the best customer service I’ve ever had from any guitar store but they mainly carry ESP (which if you’re interested, try ESP’s Amaze jazz bass. I played it next to a Lakland and Sadowsky and much preferred the ESP). But there are loads of other stores like Guitar Planet, Ishibashi Gakki on the 3rd floor, and Kurosawa Gakki, which are my go-to.
Someone mentioned TC Gakki in Shin-Oukubo but the last 2 times I was there, there weren’t that many interesting basses, but you may want to give it a try. There’s a Kurosawa Gakki down the street from TC Gakki, but I don’t recommend going to that Kurosawa. Ya, they have interesting basses there but they were d**ks to me. I was trying a Serek (first time) and they wanted me to give it back after about 2 minutes of playing. Some people do that with foreigners (even though I’m technically not).
One important thing, if you want to try an instrument, you have to ask the store clerk. You can’t just pick up any bass and start playing. You ask them, and they’ll tune it up for you even if you know how to tune your own instrument.
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In terms of places to visit, there are mainly 3 spots I'd recommend:
- Ochanomizu: many big stores here, including Guitar/Bass planet, The ESP/Boss store, Ishibashi, Shimamura (or Shimokura? I forge which one is where), etc.
- Shibuya: Ikebe bass collection & Grandey's Bass (BC does the 'high end' stuff, Grandey's is the more usual stuff), Kurosawa Gaggki G-Club, Key Music, and I think there's also an Ishibashi in there somehwere,
- Okubo/Shin-okubo area: Kurosawa 'Bass Center', Barchie's Music, and TC Gakki
There are also some other instrument shops at other major stations (e.g. Ikebukuro has an Ishibashi & Ikebe Rock House, and Shinjuku has couple too), but if you want to visit the most bass/guitar focused places, then the above thee areas/stations should keep you busy for a few days.