[NTREEG]

I've seen 2 music stores in Shinjuku. It's hard to describe where they are though and I can't remember their names. From Shinjuku station's East entrance, if you turn right and go to the area near Sakura and Bic Camera, there's an area where there's a McDonalds and Wendy's right across the street from each other. Maybe a block or two away from there (but possibly on another street) there's a store selling nothing but guitars.

There's also another music store not too far from Iseten and Marui (OI) City department stores. They sell all kinds of instruments there. I'll likely be heading into Shinjuku some time today so I'll try to get the names of the stores and some more detailed directions for you.

People also say Ochanomizu has a ton of guitar stores. I've been to Ochanomizu often but I've yet to see those stores. However, I've never been looking for them either.