Guzheng Tuner — 21 Strings in D Major Pentatonic

A guzheng is a Chinese plucked zither with 21 strings, most often tuned to the D major pentatonic scale — D, E, F♯, A, B — repeated across about four octaves from D2 (73.42 Hz) to D6 (1174.66 Hz) at A4 = 440 Hz. Each string crosses its own movable bridge and ends at its own tuning pin.

How to use it

1. Start the tuner. Press Start Tuner (Microphone) and allow microphone access. The audio is analysed in your browser; nothing is uploaded.
2. Read the cards in instrument order. The board runs from the 21st string (D2) at the top to the 1st string (D6) at the bottom, which is how the strings are numbered on the instrument. It is not a low-to-high list you can assume — it is the physical numbering.
3. Pluck the speaking length, right of the bridge. Guzheng 箏 Alive’s tuning guide is explicit: check each string’s pitch by plucking its right side, because the left side is the length you bend rather than the length you tune to.
4. Mute the strings on either side. The five notes repeat in every octave and several strings sit a fifth apart, so a neighbour ringing in sympathy is a common cause of a jumping reading. Rest the side of your free hand across the adjacent strings.
5. Start from the 8th string if nothing else is in tune. It is A4 = 440.00 Hz and matches concert pitch exactly, which makes it the easiest string to anchor to a piano, another instrument or your ear. Then work outward, one string at a time.
6. Adjust the tuning pin a little at a time, and lift first. Before turning a pin, lift the string clear of its bridge so the tension equalises along its whole length, then turn the pin in small increments. Guzheng 箏 Alive warns never to change a string’s pitch by more than a half step between lifts.
7. Move the bridge only for fine adjustment. Once a string is within about 20 cents, its bridge is the finer, more stable control: shifting it toward the right end raises pitch, toward the left lowers it.
8. Expect a second pass. Settling one string changes the tension across the soundboard, so the strings you set first may drift slightly. Work through the 21 cards once, then check them again.

The 21 strings in D major pentatonic

The scale is five notes — do, re, mi, so, la — with no fa or ti among the open strings. In D that is D, E, F♯, A and B, repeated in every octave. The preset above uses the notes and register documented by Sinin et al., Acoustics of the Guzheng (BioResources 21(2), 2026), whose measured string set runs D2 = 73.41 Hz to D6 = 1174.7 Hz; the tuning is corroborated by Tonalics’ 21-string guzheng reference (string 21 = D2, string 16 = D3, string 11 = D4, string 8 = A4) and by Guzheng 箏 Alive, which marks the key of D as the most common for a 21-string instrument.

String	Note	Frequency (A4 = 440 Hz)
21st (lowest)	D2	73.42 Hz
20th	E2	82.41 Hz
19th	F♯2	92.50 Hz
18th	A2	110.00 Hz
17th	B2	123.47 Hz
16th	D3	146.83 Hz
15th	E3	164.81 Hz
14th	F♯3	185.00 Hz
13th	A3	220.00 Hz
12th	B3	246.94 Hz
11th	D4	293.66 Hz
10th	E4	329.63 Hz
9th	F♯4	369.99 Hz
8th	A4	440.00 Hz
7th	B4	493.88 Hz
6th	D5	587.33 Hz
5th	E5	659.26 Hz
4th	F♯5	739.99 Hz
3rd	A5	880.00 Hz
2nd	B5	987.77 Hz
1st (highest)	D6	1174.66 Hz

Pins, bridges and how the pitch is set

A guzheng string has two pitch controls, and they are not interchangeable:

• The tuning pin sets fine pitch. Guzheng 箏 Alive’s step-by-step guide describes turning the pins in small increments, working around the instrument and re-checking, with new strings taking a couple of weeks of daily turnings to settle.
• The bridge sets the speaking length. Each string crosses its own movable bridge; shifting the bridge toward the fixed end shortens the length that vibrates and raises the pitch, and sliding it away lowers it. This is the bigger lever, which is why it is reserved for larger corrections and for changing key.
• Bridge position is also what changes key. Players do not walk all 21 pins into a new key; they shift a handful of bridges, commonly the ones under the B and E strings, and the five-note pattern lands in G or C pentatonic instead of D. Guzheng 箏 Alive publishes bridge charts for the common keys.
• The bridges sit in groups of three and two. The gaps are where the missing fourth and seventh scale degrees would be. The grouping is a visual map of the scale and the space that lets the same instrument reach neighbouring keys.

Bending, the left hand and what the display will tell you

Guzheng music leans on pitches that are not available as open strings. The open strings are scale degrees 1, 2, 3, 5 and 6 — D, E, F♯, A, B — and the fourth and seventh degrees are reached by pressing the string down to the left of its bridge, which raises its pitch. The same technique produces vibrato and the characteristic portamento bends.

That has two consequences for tuning:

• Touching a string left of the bridge deliberately reads sharp. A reading that climbs the moment your left hand presses is correct technique, not a tuning fault. Tune from the open string only.
• A string can pass a microphone check and still be wrong for the player. If the open note is right but every bend sounds off, the bridge placement rather than the pitch is usually the thing to look at.

Accuracy and limits

• Tune one string at a time. The 21 strings are close together and several share octave or fifth relationships, so unplayed neighbours ring in sympathy and can take over the reading. Mute them with the side of your free hand.
• Check the octave, not just the letter. D appears five times across the instrument. A reading of D with the wrong octave number still shows the letter D; compare against the card for the string in your hand.
• The lowest strings are the difficult end for a microphone. Small laptop and phone microphones are least sensitive to the low end of the instrument’s range, so the 21st and 20th strings arrive quieter than the middle of the instrument even when they sound full in the room. Pluck them a little more firmly and let the note ring.
• A string that is far off may have a moved bridge. A large error is a bridge-position problem more often than a pin problem, and correcting it with the pin alone risks over-tensioning the string. Check bridge placement before you wind a pin a long way.
• Room noise competes with a quiet pluck. Air conditioning, traffic and other instruments all produce unstable readings. The page is happiest in a quiet room with a normal playing pluck rather than a hard one.
• Temperature moves the whole instrument. A guzheng carried into a cold room arrives flat across many strings; let it settle for a few minutes and tune, then re-check.

Safety

• Lift the string before you turn anything. Tension concentrates at the movable bridge. Lifting the string clear lets it equalise along its length, which is how players avoid snapping strings while tuning; Guzheng 箏 Alive treats this as the core of the process.
• Never change pitch by more than a half step between lifts. Large jumps are the classic way to break a string. Work in small increments and re-check.
• Do not force a stiff tuning pin. If a pin will not turn, stop and check the string and the pin rather than applying more force.
• Never tune a string an octave above its target. The 1st string target is D6 = 1174.66 Hz. An octave above that is roughly double the tension the string is designed for.
• Treat old and reused strings with care. Guzheng 箏 Alive warns that reused strings commonly snap near their ends, and that new strings need frequent small adjustments for about two weeks before they hold.
• Protect your hearing. A guzheng is loud under the hands. Take breaks during long tuning and practice sessions.