Joe's chart is good and lays out the "keys" of the sheet music at the top in keyboard note order.
Since I had already committed the Circle of Fifths (or 4ths) to memory for diatonic use, I use the Circle and position numbers to get the same results. The position numbers are all relative to the home key of the instrument, which is designated "1st" position.
In the circle of fifths moving clockwise goes by 5ths and counter clockwise by 4ths. In the circle of fourths clockwise goes by 4ths and counterclockwise by 5ths. Either will work, you just have to notice the direction of the circle.
You should look up the circles so this doesn't seem so complicated. It really is not as confusing as reading it may seem.
Starting from C on one side is G (2nd position for a C instrument), and on the other side is F (12th position on a C instrument).
The position (location of the scale on a given instrument) for playing Eb music on a C instrument is called (C-1st, F-12th, Bb-11th, Eb-10th) Tenth position (Eb position per Joe). On an A chromatic 10th position is (A-1st, D-12th, G-11th, C 10th). C is Tenth position on an A instrument!
I did this without looking at a Circle of Fifths, because I know it after having organized my keyed diatonic instruments in that order before playing keyed chromatics. Instead of memorizing the circle I just used it regularly to choose instruments from my set of 12 diatonics.
The music I play seldom has sheet music, just lyrics and chords at best, so I use keyed instruments and my ear. Since I already could play chromatic harmonica in a few keys, keyed chromatic harmonicas allowed me to play and improvise in all keys with a shorter learning curve than doing it all on a C instrument. Using chromatic instead of diatonic on some songs gave me access to all the sharps and flats without learning extensive overbending on a diatonic.
I play Americana, folk, and roots music and different singers and different bands frequently change the key of a song, so this approach works well in these circumstances. If I were intent on playing classical or standards in the original keys, I would focus on learning it all on a C instrument and not go the keyed chromatic route.
From my experience, most keyed harmonica players either organize by the circle of fifths (or 4ths) or by keyboard scale note order.
The circle of fifths gives other information as well, specifically the order in which sharps and flats are added to keys.
Doug S.
