This is an appendix to the Otona no Kagaku Magazine Vol. 17, released on September 28, 2007. https://otonanokagaku.net/magazine/vol17/index.html I bought it when it was released and assembled it, played with it a little, and then stored it for a long time. I have confirmed that it works without any problems. A reprint was released, but this is the original version and does not have a ground, so it requires very delicate operation and is difficult, but it's fun when you can make sounds successfully. It has a built-in speaker, so everyone can enjoy the sound. You can also enjoy modifying it. You can connect it to an external amplifier (commercially available) with simple modifications.