The cittern we're talking about here is the 10-string long-scale bouzouki, probably first named as such by Stefan Sobell, the famous luthier. This instrument, when tuned in fifths like a mandolin/mandola, CGDAE, becomes an extraordinary jazz instrument in that it models music theory very, very well. The extra course really extends and helps to illustrate the wonderful symmetries available in fifths tuning, and makes chord building and scale visualization a breeze. So much so that, we can imagine a day when fifths tuning is the standard, and the mighty Cittern rules the world!
So, in view of its inevitability, it's best to start preparing now.
Chords for the Cittern
The fifths symmetry makes the most sense for chord building if you don't need to rely on open string tunings. There are tons of efficiencies that come from extending the standard mando tuning down another fifth.
For example, you can find typical mando 4-string chord shapes right next to each other on the neck, and combine them out to 5-string if desired (see
Mandolin Lessons on this site). Here we're doing it with the first and third inversions of the 4465 shape (B7) to get the 3 and 7 on the bottom, but you can find these neighboring shape relationships in all cases, and it's important to learn them all.
Notice how the two shapes are adjacent in two places on the neck.
Similar things can be accomplished with all chord shapes. The root and second inversions will be found adjacent, and the first and third will be found adjacent in the same way thanks to that magical fifths tuning.
Visualizing Patterns: Perceptual Economy
One of the first things to try to get strated on fifths-tuned instruments is to find the intervals of the major scale (w-w-h-w-w-w-h) and see how the relationships laid out on the neck. The beauty of the consistent fifths (as opposed to standard guitar tuning) is in the symmetries you find on the instrument. The major scale, for example, produces a nice compact symmetry that makes complete visualization and navigation of the instrument a snap. No surprises here:
===|===|===|===|===|===|===|===|===|===|===|===|| C
===|===|===|===|=0=|===|=0=|===|=0=|=0=|===|=0=|| G
===|===|===|=0=|=0=|===|=0=|===|=0=|=0=|===|===|| D
===|=0=|===|=0=|=0=|===|=0=|===|=0=|===|===|===|| A
===|===|===|===|===|===|===|===|===|===|===|===|| E
(<- Body -- Nut ->)
The symmetry is actually discovered on the second degree of the major scale (shown in
orange above) which is the tonic of the dorian mode (the ii of the major scale). Call this the pivot. This yields the dorian intervals going up the scale from the pivot, w-h-w-w-w-h-w, and the same pattern going down from the pivot, w-h-w-w-w-h-w. It really makes navigation on the instrument a breeze. We're not talking about putting it on autopilot and playing junk - Rather, the predictability eliminates a lot of work. Perhaps we can refer to it as "perceptual economy", i.e., symmetry=simplicity, lack of symmetry=complexity.
The symmetries are even more easily recognized on citterns with the extra course than the four-course instruments - It's easier to see how these things play out on the five courses. Six strings really brings it out, so you may want to try tuning that guitar in fifths!
The Cittern and the Ubiquitous II-V
Fifths tuning has a natural "tetrachordal" layout. You can easily do an octave scale on two strings and six or seven frets. This means you would naturally switch strings at the fifth going up the scale.
Because of this, another advantage to fifths tuning is how very well it reflects II-V changes. Similar to guitar, changing keys a fourth or fifth is as easy as shifting over a string, only minus the odd guitar G/B tuning speedbump. Notice in the graphic below we are traveling in fourths, cycling around the neck, using our symmetry from above. Also omitted are the top and bottom notes of the blocks to visually separate them a little better, and they are colored in red and blue so you can easily see them modulate: