Great museum - well worth the visit if you are ever in Hamamatsu! The collection is not humungous - I saw everything in less than 2 hours - but it is very well curated and best of all there are recordings of most things that you can listen to and the self-guided tour includes a lot of information and interesting stories. I don't speak Japanese and had no problem navigating the museum (the self-tour is also in English). There's even an instrument you can play with instructions that will let you make passable music within a few minutes!

I was also surprised to see an entire room full of electronic instruments though these were not well curated - they had minimal descriptions, were not part of the self-tour and did not include recordings. Hopefully this section will be expanded in the future; at a minimum they should include the theremin in this room (the first electronic instrument!) And, while I was impressed they had the entire Roland Aria series, it was odd that they had no examples of the original instruments these were copies of (like the TB-303 and TR-808). But I assume the electronic section was a recent addition and the rest of the museum is very well laid out. Love it!