This is a practice app for the “shō” instrument used in Japan’s traditional court music, gagaku.
The notes in Western music known as chords are called “Aitake” here, and you can visually confirm the Aitake notes.
Comparing them to Western musical notation aids understanding.
Supports the standard Western pitch of 440Hz.
https://apps.apple.com/us/app/sholearn/id6759441006