Guide tones
Guide tones are the 3rd or the 7th in a chord. They are often viewed in the context of soloing, especially in jazz. The reason why not the root or the 5th are guide tones is that they don’t effect the chord being a major, minor or dominant.
Guide tones in various chords
The table shows the guide tones in different chords:
| Chord | Guide tone | Guide tone |
|---|---|---|
| Cmaj7 | E | B |
| Dmaj7 | F# | C# |
| Emaj7 | G# | D# |
| Fmaj7 | A | E |
| Gmaj7 | B | F# |
| Amaj7 | C# | G# |
| Bmaj7 | D# | A# |
| C7 | E | Bb |
| D7 | F# | C |
| E7 | G# | D |
| F7 | A | Eb |
| G7 | B | F |
| A7 | C# | G |
| B7 | D# | A |
| Cm7 | Eb | Bb |
| Dm7 | F | C |
| Em7 | G | D |
| Fm7 | Ab | Eb |
| Gm7 | Bb | F |
| Am7 | C | G |
| Bm7 | D | A |
Besides four-note chords, there are obviously guide tones in triads as well as extended chords. The list above helps you out regardless of the chord. For example, the guide tone of a C major is E and in a C minor it's Eb. Consequently, the guide tones in Cmaj9 are E and B, in C13 they are E and Bb and so on.
As said, guide tones are mostly relevant when it comes to soloing. They are not the same thing as target notes, which are any note of the chord.
Nevertheless, guide notes are also of interest from a harmonically perspective and can point out which the most vital notes in a chord. Often chords are not played with all notes. The root may be omitted and handled by the bass player and also the 5th is commonly left out. Only playing the 3rd and the 7th, will in many cases reveal which chord that is implied. For example, G# and D will imply a dominant E seventh. One method of jazz comping relies on using primarily two notes in this way.
See also Chord theory | Music theory.