Key of C: What does it mean to “play in the key of C”?
What does it mean to play in the key of C? It means you are basing your playing on the scale of C which has no sharps or flats in the key signature. To play proficiently in any key you need to know not only the scale of that key, but the primary and secondary chords in that key.
Watch this short video on how to play piano in the key of C:
For an entire course on How To Think In The Key click here.