[balfirevic]

> The easy answer is that the piano is not the "reference" instrument.

The question make sense without ever thinking about piano. The question is: how come the notes named only by letters (without any accidentals) form a major scale, and yet the note A is not the first note (or tonic) of that scale.

The answer is probably related to the fact that those notes also form other scales (seven of them - seven diatonic modes, one of which corresponds to major scale), and it's only relatively recently that the major scale took a central role in music theory.

[amszmidt]

You will need to blame Boethius, musical notation is a quagmire of many systems that have been merged over centuries. If you venture into non-western systems, it becomes even more fascinating.

Maybe we should make one more standard .. that consolidates all of them? ;-)