Simple movement games
The major and minor central chords discussed in the previous section provide a way to give listeners a sense of a home location that can be started from, roamed away from, and returned to. This makes all sorts of simple movement games possible. NB this will probably make most sense if you play with it yourself using harmony space, or watch the video <here>.
In broad terms, one idea is to limit yourself to the three major chords in a given key window. Following this idea, broadly the central chord is treated as a home or final point, and the two other major chords are treated as distinguishable other places. Some musicians call this the ‘three chord trick’. However this constraint leaves a vast amount of freedom, making it possible to provide harmonic accompaniment to thousands of popular songs, hymns, the blues, children's songs, etc. In the case of the blues, the order of chords is broadly fixed, whereas in many other genres the order of chords may depend on a melody.
Example of a major three chord trick.
Only the roots of chords are shown in this diagram. For many songs with this patterns see <here>
As well as the major three chord trick, there is also the minor three chord trick. For numerous example see <here>
Example of a minor three chord trick. Only the roots of chords are shown in this diagram. For many songs with this patterns see <here>
This arguable does not sound very interesting, as structure gets completely lost for an extended period in the black “forbidden” area. But it is worth seeing at least once.
The minor three chord trick, but this time displayed using roman symbols, to generalise it to any minor key.
In the minor mode, for reasons discussed here, the V chord will often be played as a major chord.
A related idea is the ‘four chord trick’. See examples <here>
An example of a major four chord trick. (The example path shown here is the Sam Cooke song “What a Wonderful World”, covered by Paul Simon, also known as “Don’t know much about history”)
The major three chord trick, but this time displayed using roman symbols, to generalise it to any major key.
The four chord trick, but displayed using roman symbols, to show the pattern regardless of which of the 12 notes of the chromatic scale is used as the home note (i.e. generalised to any key).
But more elaborate journeys around chords are clearly possible. It is hard not to notice various ‘runways’ of increasing length, all aiming directly at the major home location.
Another straight line runway, this time of four chords. Because the ‘trace root” button is on, only roots are recorded in this trace. After the four clicks needed to produce these chords, the ‘print chords’ button has been used to print out the chord quality of each chord.
A straight line runway of five chords ending at the major tonal centre. This kind of thing happens a lot in baroque music and in Jazz.
There is apparently only a much shorter straight line runway in the opposite direction. However, with a bit of work, interesting things can be done moving in this direction <Hey Joe> <plagal cadences> <mixolydian cadences>
A straight line runway of three chords ending at the spatially central major chord. In this case, three clicks in Harmony Space produce the chords D minor, G major, C major (squeezed into shape by forces described here).
A wonderful feature of these ‘runways’ is that when the root moves down the runway, listener can generally tell intuitively from the changing pattern of chord qualities ( i.e. major or minor) not only when they have reached home, but when they are about to reach home, and in simple cases, how many steps it will take to reach home.
Taking the runway idea to one extreme, you can set off from home in a consistent direction till you reach home again. There are two ways to do this. To play it diatonically, just skip over the forbidden black area and continue the motion when you reach land again. The diatonic version moves in what is called a diatonic circle of fifths. There are several different ways to draw this. Which ever way you draw it, where the discontinuity occurs, there is a jump of a tritone (six semitones, or two steps vertically upwards).
A straight line trajectory from the tonal centre D to the tonal centre D that totally ignores and skips over the white area (known in the trade as a “diatonic circle of fifths”). J.S. Bach uses this kind of things a lot to good effect.
We can easily draw exactly the same thing a different way that emphasises what a tritone leap (in this case from G to C#) looks like in a single key window.
Same thing, shown using a slightly different route.
Instead of following the straight line but ignoring the black area you can plough through it regardless. This is known as a chromatic cycle of fifths. Chords in the forbidden black area are not well defined by the rules of the diatonic scale, but one reasonable fall-back option is to play them all as major, or as dominant chords (a common jazz fall back).
Many songs use a diatonic circle of fifths.
Some starting and finishing with the major tonal centre, and some starting and finishing with the minor tonal centre. For example<>
Many of the chord progressions shown above, though structurally important, have been overused to the point of cliche. However this charming straight-line trajectory from the minor tonal centre back to the minor tonal centre still sounds fresh. Note that the dog-leg kink kind really just corresponds to missing out the black forbid (i.e. non-diatonic) part of the trajectory. Note also the dominant 7 on V to give closing cadence, as explained here.
It can make a lot of musical sense to combine the above patterns. For example, some pieces combine a three chord trick with a diatonic circle of fifths. This can be done in both the major and minor cases.
To a good approximation, The lady is a Tramp, as performed by Frank Sinatra combines a three chord trick, a four chord trick and a diatonic circle of fifths <see here>
To a slightly more approximate degree Street Life, performed by Donna Summer, combines a minor three chord trick (with and without the cadential domination seventh at different points) and a minor diatonic circle of fifths <see here>
This does not begin to scratch the surface of the possibilities of simple movement games let alone more sophisticated tactics and strategies.
One emerging effect of these common patterns is that locations within the key window start to attract recurring roles, or jobs, or functions. For example, consider one very prominent position on the downward runway, the position just before reaching home. When played as triad, the chord quality is the same as the other two major chords in the key window, so in the absence of movement, on hearing that chord quality you could be in any of those three positions. However, if you choose to build a four-note chord in this position, something structural emerges, as discussed in the next section.
Previous … Where is home?
Next…. Emerging Chord Function