A full version app for Android, by WeSoftLab.

This application is based on the idea that you can use the circle of fifths as a method of finding out the key of a song you want to learn. It is a very useful application because it allows you to learn the key of any song. You just need to enter the name of the song and you will get all the information you need. The application also allows you to find out the name of the song, the name of the composer, and the year in which it was written.

The application is based on music theory. In this theory, the circle of fifths is the relationship among the 12 tones of the chromatic scale, their corresponding key signatures, and the associated major and minor keys.