How To Build Keys
What are the rules behind the keys we use? And how can you build a key if you don’t have a table to reference? If you have ever asked those questions then this is the page for you! Credit for the idea goes to L. Nguyen. Thank you!
How to do it
(Assuming a 21-string guzheng and major pentatonic keys).
1) Pick your key say, D Major. Build your major pentatonic key using the 1, 1, 1.5, 1, 1.5 step pattern: D, E, F#, A, B.
2) Label your scale degrees. Since we are using pentatonic scales we skip 4 and 7: D=1, E= 2, F#=3, A=5, B=6.
3) Find F# or G on the scale. F# or G is the pitch for string #9 on your guzheng.
4) Find the scale degree for F# or G. This is the notation for string #9. The actual pitch is the F# or G in the same octave as middle C: F#4 /G4.
5) You now have enough to build your scale! The next largest string number is always one scale degree down. In the case of D Major, String #10 will be 2, or E. String 11 will be 1 (D), String 12 is 6-one-dot-below (B) and so on. The next smallest string number is always one scale degree up. String #8 will be 5 (A) and so on.
6) Make sure to space your bridges. Scale degrees 1, 2, and 3, should be in a group of three, and 5 and 6 should be in a group of two. There should be noticeable space between the groups. This pattern is true for every key.
And there you go! Go ahead and give it a try. Check your outcome against the chart on the Keys page. Read on for the theory behind it.
Note: 10 of the pentatonic major keys have F# or G. The remaining two keys (C#/Db and G#/Ab) don’t follow this rule, but then, I have yet to see them used on guzheng music.
Why this works
Let’s first define some words. A Scale is a sequence of notes that follow a specific pattern. A Key is the scale that a piece of music uses. Musical instruments like guzheng can be tuned to make playing songs in a given key easier or more enjoyable. We call that tuning them to the key of ___. For our purposes Scale and Key are interchangeable. Music theorists, please forgive us.
Scales are named in the format (Staring Note) (Type). Each type has its own sequence. There are MANY types and subtypes and each have different rules for their sequences. Thankfully, we only need two types: the Major Diatonic and Major Pentatonic scales.
We count the notes in a scale with numbers. We call each place in the scale a scale degree. The 1st scale degree is the first note of the scale, the 2nd scale degree is the next highest pitch, and so on.
Let’s start with a Diatonic scale.
A Diatonic scale contains 7 notes. A Major Diatonic scale contains 7 notes with the following pattern of whole steps (w, 1) and half steps (h, 0.5) between scale degrees:
1 w 2 w 3 h 4 w 5 w 6 w 7 h (8, or one octave higher than 1).
To build a Major Diatonic scale, then, pick a note and move up the pitches with the pattern wwhwwwh.
We can see this with the D Major Diatonic scale. That “D” tells us the first note or 1st scale degree is the note “D”. One whole step up from D is E (2nd). One whole step up from E is F# (3rd). One half step up is G (4th). One whole is A (5th), one more whole is B (6th), one last whole is C# (7th). Finally, one more half step brings us back to D (8th or 1).
Now let’s compare that to the pentatonic scale.
A Pentatonic scale has 5 notes. A Major Pentatonic has five notes with the step pattern w, w, h + w, w, w + h. (1, 1, 1.5, 1, 1.5) This is the same as if we skipped the fourth and seventh notes in the Major Diatonic scale. So let’s skip those scale degrees and see what we get: 1, 2, 3, 5, 6. Doesn’t that look an awful lot like your sheet music? Surprise! The strings of guzheng are notated based on their scale degree!
So! We know the pattern, the pitches, and the notation for the notes of a scale. Now we just need to connect them to our physical strings.
The secret to constructing the key for a guzheng is string #9. String #9 is F# or G in 10 of the 12 major pentatonic keys. Therefore, if we can identify which pitch will be in our key and find its scale degree, we can build everything else.
A few notes: The remaining 2 keys, C#/Db and G#/Ab are rarely used, so I haven’t covered a system for them. String #9 is the F# or G string for 16-, 18-, and 21-string guzheng. For 23-string it’s #10, and for 26-string, #11.
Actually for 10 of the major keys it is in the home octave, no dots above or below. Find F# or G in your chosen key. Find its pentatonic scale degrees: 1,2,3,5, or 6? That is the pitch and the sheet music number for string 9.
Next, work through the neighboring strings. String 8 will be one scale degree higher than string 9. String 10 will be one scale degree lower, and so on.
(In scientific/piano notation, the pitch for string 9 is either F#4 or G4. Middle C is C4.)
Match the other 4 notes in the scale with the neighboring strings. That is your home octave. Repeat the pattern for the rest of your instrument.
And there you have it a! A look into the theory behind guzheng key constructions.