Guzheng are usually tuned to pentatonic scales. The open strings are scale degrees 1, 2, 3, 5, 6. You reach 4 and 7 by bending scale degrees 3 and 6. If you want less bending and more plucking a diatonic scale will work for you. If you want to play traditional music use the Pentatonic Tunings instead.
There are two main ways to tune a guzheng diatonically:
1: Buy a set of diatonic strings. These are known as “Type C” strings and are calibrated to work for the balance of thickness, tension, and length you’ll need. THIS IS THE RECOMMENDED METHOD. But maybe you don’t have access to Type C strings. In that case:
2: Get duplicate strings (Type A or B) and tune your instrument manually. Using the following example from Carol Chang, you’ll need duplicate #17, #14, #12, #9, and #7 strings.
First decide what range of notes you want. A guzheng in the pentatonic Key of G will range from D2 to D6, 4 octaves and 1 extra string. A diatonic tuning will only span 3 octaves. Your bass strings will be higher than normal and your treble strings will be lower than normal. Use the songs you want to play as a guide. Write the lowest and highest notes down. If they span more than 3 octaves you won’t be able to use this tuning.on In our example we’ll use a range from G2 to F5. (You can use an online tone generator to help.)
Once you have your notes you’ll need to figure out which string thicknesses you can use. A guzheng string is designed to be tuned about one half step higher or lower than what they are set to in the Key of G. Strings may tolerate up to one whole step. Go farther and you will snap strings. Following our example, a #21 string WILL BREAK or damage the guzheng if we tuned it to G5. That’s 2 and a half steps or 5x higher than the expected range. Instead we’ll use a #19 string. #19 is tuned to G2 in the pentatonic key of G so that’s perfect. Put a #19 string in position 21.
The next higher note is A2. Great, #18 strings are tuned to A2 in key of G. Put a #18 string in position 20. Position 19 would be B2, which is normally a #17 string. Excellent. That brings us to position 18.
This diatonic scale calls for C3 in position 18. If we go to our Key Table you’ll see the #17 string can be tuned to C3 in the Key of C. So, we’ll put a second # 17 string in position 18. See the full writeup below. We also duplicate strings for F and G.
Position: the location on the instrument. String #: thickness. See your string’s packaging to record what string thickness you are using. On pentatonic tunings the string # is the same as the position. ##cm: The distance between the right fixed bridge and the movable bridge. The conversion from centimeters to inches is rounded for your convenience.
Position = Note = String # = Distance
Position 21 = G2 = String #19 = 73.5cm (29in)
Position 20 = A2 = String #18 = 71cm (28in)
Position 19 = B2 = String #17 = 68.5cm (27in)
Position 18 = C3 = String #17 = 66cm (26in)
Position 17 = D3 = String #16 = 63.5cm (25in)
Position 16 = E3 = String #15 = 61cm (24in)
Position 15 = F3 = String #14 = 58.5cm (23in)
Position 14 = G3 = String #14 = 56cm (22in)
Position 13 = A3 = String #13 = 53.5cm (21in)
Position 12 = B3 = String #12 = 51cm (20in)
Position 11 = C4 = String #12 = 48.5cm (19in)
Position 10 = D4 = String #11 = 46cm (18in)
Position 9 = E4 = String #10 = 43.5cm (17in)
Position 8 = F4 = String #9 = 41cm (16in)
Position 7 = G4 = String #9 = 38.5cm (15in)
Position 6 = A4 = String #8 = 36cm (14in)
Position 5 = B4 = String #7 = 33.5cm (13in)
Position 4 = C5 = String #7 = 31cm (12in)
Position 3 = D5 = String #6 = 28.5cm (11in)
Position 2 = E5 = String #5 = 26cm (10in)
Position 1 = F5 = String #4 = 23.5cm (9in)
Note: This spacing has not been tested. It is based on theory. Use your judgement.
Bridges are normally positioned in sets of 2 and 3 to allow shifting between pentatonic keys. If you are tuned diatonically you have less need of this. So, consider spacing the bridges equally. See the table above for where you may want them. If you find these placements seem to demand too high of a tension, shift your bridges closer to the right. You may need to experiment a bit to find the right balance. If you did even spacing you want roughly 2.5 cm between bridges, which is about one inch.
Place your Position 1 bridge about 23.5cm or 9.25 inches from the right fixed bridge. Place your position 2 bridge 2.5cm or 1 inch to the left. keep doing this for all your movable bridges. Your final bridge should be about 73 cm from the right fixed bridge (about 29 inches).
Bridge Position 1 and Position 21 are based on the distance that string # would normally have if it was tuned to that pitch on a pentatonic instrument.
Note: This spacing has not been tested with key changes (shifting strings to flats or sharps). You may not have enough room to move your bridges far enough. You can either change your string tensions or redo the spacing to try and find that space.