Koto Instrument is a free multimedia Android application developed by PTD Studio. As the name suggests, the app is dedicated to the traditional Japanese stringed musical instrument - koto (箏). The app provides a realistic koto playing experience with its multi-touch and swipe support, and studio-quality sound. The sound intensity varies depending on the touch position, making it feel like you are playing a real koto.

Koto Instrument offers a highly customizable interface, allowing users to choose from a range of string colors and beautiful animation effects. Moreover, users can record their audio while playing and save it for future playback. The app also features a list of recorded files that can be played back at any time. The developer promises to update the app monthly by fixing any bugs and adding new features.

Overall, Koto Instrument is an excellent app for those who want to experience the traditional Japanese musical instrument on their Android device.