There are two different ways to use Solfège: “Fixed Do” and “Moveable Do.” In some countries, a Fixed Do system is used, where Do always means C. However, we find it most helpful to teach using both a fixed system (ABCDEFG) and a movable system (Do, Re, Mi, etc.). Some kind of fixed system is essential to provide structure and certainty. D is always a D on the piano or on any instrument. However, a movable system is best for helping students easily hear and recognize the function of each note in a scale and relationships between each note in a melody, no matter what key the music is in. So, we try to give students the best of both worlds by actively using letter names as a fixed system and Solfège as a movable system. You can learn more about Solfège in our blog post, What is Solfège?