Keyboard instrument, in particular a piano or similar instrument that has keys and that can be used in conjunction with aids to learning in the form of templates, characterized in that, of the white keys (long keys 2) that form the C-major scale, the width (b) of the keys that produce the notes B, C, E, and R is 1/4 less than the width (B) of the remaining keys, which produce the notes D, G, and A, so that the ratio of the width of the equally wide keys for B, C, E, and F to the width of the equally wide keys for D, G, and A is 3:4. Templates that are separated into a number of adjacent divisions (5) that are equally wide, each division (5) being 1/2 the width (b) of one D, G, or A key, so that three adjacent divisions (5) will be as wide as two B, C, E, or F keys and two divisions (5) will be as wide as one D, G, or A key can be placed over the keyboard to represent all possible scales, thirds, triads, and tetrads with their inversions, major and minor intervals, cadenzas, transpositions, etc.