Over the years there have been various different methods used to write chord symbols. Jazz evolved from using simple harmony back in the old days to quite complex harmony that was made popular by the bebop innovators, which used upper extensions (9ths, 11ths and 13ths etc.), and chromatic alterations (b5, #11 etc.).
In early music triads were often used so a chord symbol could be as simple as C (for a C major triad) and Cm (for a C minor triad).
Early sheet music started to include chord symbols, but very often they were written with banjo players in mind and (rightly or wrongly) were simplified. Serious jazz composers needed to invent symbols rather than notation as it was much more conducive to the creative and spontaneous process of jazz improvising.
Chord symbols can work best when they are as short as possible, otherwise sheet music can become very cluttered, but be careful they aren’t confusing, especially when written by hand in a hurry.
Common chord types with alternative symbols
- The symbols in red are recommended as some of the others can be confusing (especially “-” for minor and “alt”> for altered forms of 9 and 13.
- The triangle symbol can be useful for major 7 (Δ or Δ7) when in a hurry, but be careful as it can sometimes look like a badly drawn
- The capital
Mfor major 7 can also be confused for lower case “m”>.
|C major 7||Cmaj7||Cma7||CΔ or CΔ7||CM7|
|C minor 7||Cm7||Cmin7||C-7||–|
|C minor major 7||Cm maj7||Cmin ma7||C – Δ7||C –|
|C half diminished||Cø7||Cm7 b5||Cmin7 b5||–|
|C diminished (7)||Co (7)||C dim (7)||–||–|
|C7 suspended 4th||C7 sus4||–||–||–|
|C7 augmented||C+7||C7 aug (C7+)||C7+5||–|
|C7 flat 5th||C7 b5||C7 -5||–||–|
|C7 #11||C7 #11||C7 +11||–||–|
|C7 flat 9th||C7 b9||C7 -9||–||–|
|C7 sharpened 9th||C7 #9||C7 +9||–||–|
|C7 flat 10th||C7 b10||C7 -10||–||–|
|C7 flat 9th flat 13th||C7 b9 b13||C7 alt||–||–|
|C7 flat 10th flat 13th||C7 b10 b13||C7 alt||–||–|
|C13 sharp 11th||C13 #11||C13 +11||–||–|