Skip fretting system 43 2 9

One way to play 43-edo on a 21.5-edo guitar is to tune each pair of adjacent strings 251 cents apart -- a bit sharp of 15:13.

Among the possible skip fretting systems for 43edo, the (43,2,9) system is especially convenient because it makes chords in the 2.3.5.13 subgroup particularly easy to play, which is also the subgroup that 43edo is best tuned in. As a melodic system it is also excellent, since every interval can be reached with a stretch of 4 frets or less. (just over 2 on a 12edo guitar) However, it has limited range compared to most skip fretting systems, spanning just over an octave on a standard 6 string guitar. For this reason it is probably better used with instruments with more strings such as a harpejji or chapman stick, or by using multiple guitars tuned to different octaves to create a complete piece of music.

Here is where all the prime intervals lie:

note	fretboard position
0 steps = 1 % 1	string 0 fret 0
43 steps = 2 % 1	string 5 fret -1
25 steps = 3 % 2	string 3 fret -1
14 steps = 5 % 4	string 2 fret -2
35 steps = 7 % 4	string 3 fret 4
20 steps = 11 % 8	string 2 fret 1
31 steps = 13 % 8	string 4 fret -3
4 steps = 17 % 16	string 0 fret 2
11 steps = 19 % 16	string 1 fret 1
22 steps = 23 % 16	string 2 fret 2
37 steps = 29 % 16	string 5 fret -4
41 steps = 31 % 16	string 5 fret -2

From these, the location of a compound intervals N can be added by vector-summing the string-fret positions of N's factors. See Skip fretting system 48 2 13 for details on how that's done.