This was my first and probably last 4x3 sudoku. It was harder to "prepare the cheat" and write it in 1-9,a-c than to solve it - singles only, though with all the cells and digits also singles are often hidden very well. If i had done that with the notes, my eyes would have been ruined forever.
For the "preprocessing" at least 'a' was 'a' and 'b'flat was 'b'
Nice idea anyway, time to play it now ...
[Added:] Uhh, the first row is not best style. It starts with the second inversion of f major triad and ends with the first inversion of b minor triad. That's minor interesting (not to say forbidden) for 12 tone composers, as my expert told me.
Ok, we know, the facebook level is not the highest one.