MSG is the acronym for “Modified Schoenberg notation for Guitar,” by Ole Kirkeby. It is closely related to Chromatic Lyre Notation by Jan Braunstein and Clairnote by Paul Morris, as well as to Kirkeby’s newer SLING notation. The system spans 3 octaves, and staff lines are 4 semitones apart, so from bottom to top the lines are at E2 – Ab2 – C3 – E3 – Ab3 – C4 – E4 – Ab4 – C5 – E5. The E lines are full, whereas the Ab and C lines are dashed. (In an earlier version, the top three lines were dashed, all other lines were full, and the E2, E3, and E4 lines were bold.) The notation is designed for a 7-string guitar with strings all tuned 4 semitones (a major third) apart, so that each open string corresponds to a staff line. However, it might also appeal to guitarists who play in conventional tuning, since the full staff lines E2 (open 6th string), E4 (open 1st string), and E5 (1st string 12th fret) are strong visual anchors on the instrument. Kirkeby maintains a web site with information about how to play a guitar tuned in major thirds.