Silk strings: how the qin's strings came from the silkworm

A workshop. Along one wall runs a row of wooden frames, and stretched across them are dozens of threads, each five or six meters long, running from one end of the room to the other. The threads are off-white, and in the light from the window they have a faint sheen.

A man sits at one end of a frame holding a wooden wheel wound with thread. He fixes one end of the thread, hooks the other onto the wheel, and turns it, not fast, one revolution after another. Before his eyes the thread twists tight, thickens, and shifts in color from off-white to a pale yellow. After a set number of turns he stops, plucks the thread and listens.

Then he takes it down from the frame and lowers it into a basin of warm, pale yellow glue.

This thread is one of seven strings. A full set for one qin will take him several days. A few days after that it will be stretched across an instrument, and the first note it plays will be something a silkworm spun a few months before.

The strings are the voice

The Chinese character for qin (琴) has two components at the top that look like the character for "king" written twice, side by side, like parallel strings. The body of the instrument is wood and the hui, the 13 position markers inlaid along the string, are mother-of-pearl, but it is the strings that sound. The strings are the voice of the qin itself.

For more than a thousand years those strings were spun by silkworms. China has raised silkworms for several thousand years, and silk was used not only for cloth but for strings: the qin, the se, the zheng and the pipa all used silk. When a string broke, replacing it was called xu xian (续弦, "continuing the string"), a phrase that later came to mean a widower's remarriage. When Boya smashed his qin after the death of the one friend who understood his music, the act was called jue xian (绝弦, "cutting off the strings"; see Boya and Ziqi). The vocabulary of strings is the vocabulary of the qin.

How silk strings are made

The raw material is silk, and the process has four main steps.

Reeling. Cocoons are put into hot water, which softens the natural gum, sericin, that holds the filament in place. A small brush finds the loose end and the filament is drawn off. A single silk filament is far finer than a human hair, and dozens must be combined to make one strand. This is the same reeling that begins the making of silk cloth, which is why string workshops were usually found in silk country, around Hangzhou, Suzhou and Huzhou.

Plying. Several strands are twisted together in a set direction into a cord. This is what the man in the opening scene was doing with his wheel. The 1st string, the thickest, takes the most silk; the 7th takes the least. Old texts give a fixed quantity of silk for each string, measured in liang, a traditional unit of weight, and decreasing from string to string. The twist must be even and the tension constant. Otherwise the thickness varies along the string, the pitch is unreliable, and sliding notes catch on lumps.

Sizing. The plied cord is soaked in glue, traditionally boiled from fish bladder or gelatin, so that the silk bonds, straightens and does not fray. The strength of the glue, the soaking time and the drying temperature decide the string's hardness and tone. Heavy glue makes a hard string with a bright but brittle sound. Light glue makes a soft string with a thick sound that frays easily. This was every maker's secret, and each did it differently.

Wrapping. The thicker strings, the 1st to the 4th, are wrapped with a further layer of fine silk, which makes them heavier, steadier and deeper in sound. The wrapping is wound turn against turn, with no gaps and no overlaps. The three thin strings are left unwrapped.

The strings are then dried and stretched straight, and the set is finished. The Yuguzhai Qinpu ("Qin Handbook of the Studio for Communing with the Ancients", 1855) by Zhu Fengjie of the Qing dynasty (1644–1912) records the steps of string making and is one of the more detailed accounts that survive. From reeling to completion, a set takes a few days if all goes well, and about half a month once drying is included.

The seven thicknesses

The seven strings run from thick on the outside, nearest the player, to thin on the inside. In zhengdiao (正调), the standard tuning, they are tuned C D F G A c d. Thickness fixes pitch: at the same tension a thick string sounds lower and a thin one higher. The amount of silk in each string decreases in proportion, a ratio the old texts call "string divisions", and different handbooks give slightly different figures.

The strings have names. Traditionally the 1st to 5th are named gong, shang, jue, zhi and yu, the five notes of the pentatonic scale. The 6th and 7th are "lesser gong" and "lesser shang", an octave above the 1st and 2nd (see the five notes and two changing notes (in Chinese)). Legend says the sage-king Shun made a five-string qin, and that King Wen and King Wu, founders of the Zhou dynasty (c. 1046–256 BC), each added one string to make seven. It is a legend, but it explains the names: the 6th and 7th strings were later additions, and they borrowed their names from the strings before them.

Ice strings

Old texts mention bing xian (冰弦), "ice strings". In The Romance of the Western Chamber, a thirteenth-century play by Wang Shifu, the heroine Cui Yingying pours her sorrow into the ice strings, and the eighteenth-century novel Dream of the Red Chamber mentions them too. What were they?

One account says they were made from the silk of the "ice silkworm", a legendary creature of the snow mountains whose silk could not be harmed by water or fire. Another says the name simply meant silk strings of unusual whiteness and quality, and newly made silk strings really are white, like ice. In practice "ice strings" is best read as a term of praise, like "Scorched Tail" or "Green Silk", the names of famous instruments: the qin of literature. A poet did not care which silkworm spun them. What he wanted was the coolness of the word "ice".

The life of a string

Silk strings age. A new string, freshly fitted, will not hold its pitch and must be retuned for days while it stretches. Once it settles there are a good month or two when it is in tune and full in sound. After that it begins to go husky, the surface fuzzes where the left hand slides, and the wrapping on the 1st and 2nd strings works loose. Played often, a set of silk strings needs replacing within half a year.

Silk is also sensitive to weather. On damp days the strings slacken and the pitch drops. On dry days they tighten and the pitch rises. When the old players tuned before playing, it was not a ritual; the instrument genuinely needed it. And silk breaks. In a fast passage a string can snap with a sharp twang, something every qin player has experienced. A broken string must be replaced, so players kept a spare set close at hand.

In the twentieth century these troubles found a solution.

Silk and steel

After the 1950s, production of silk strings gradually stopped. The reasons were practical: silk strings broke easily, drifted out of tune and suffered in damp weather, and fewer and fewer people made them. Those who could reel silk went to work in silk factories, and nobody made strings full time for a few hundred qin players.

In the 1960s the qin master Wu Jinglüe worked with a Shanghai instrument factory to develop steel-core nylon strings, a steel wire wrapped in nylon. They held their pitch, rarely broke and were somewhat louder. From then on steel was the norm, and today almost every new qin leaves the workshop strung with steel.

The two sound different. Silk is warm and thick, with a soft attack, a short ring and a certain husky quality, and when the left hand slides, the friction between finger and string is clearly audible. Players of the past counted that friction as part of the sliding note, not as noise. Steel is clear and bright, with a long ring and little friction, closer to what modern ears expect of an instrument.

One concrete difference is in vibrato, yin (吟, narrow vibrato) and nao (猱, wide vibrato). Silk is soft, so a small movement of the left hand produces a large swing in pitch: the vibrato is clearly heard, but easily overdone. Steel is stiff, so the same movement produces a smaller swing, and the vibrato must be wider to be heard. Older players who moved from silk to steel often said steel "would not obey". Younger players who try silk after steel often say it is "too soft to grip". Both are describing the same thing.

Which is more authentic? Silk is what players of the past used, as a matter of fact. But they used it because there was nothing else. Each has its partisans. Most players today use steel, some use only silk, and some keep two instruments, one strung each way, and choose according to mood.

The twenty-first-century revival

Around 2000, silk strings began to be made again. Several makers, working from old texts and from strings surviving from the Republican period (1912–1949), restored the steps of reeling, plying, sizing and wrapping. The workshop in the opening scene is one of these. Several brands of silk strings are available today, at several times the price of steel. Silk-string making has also entered the intangible heritage lists of some localities in China.

The restoration was not easy. The old weights in liang and qian had to be converted to grams. The glue recipe had to be tested again and again. Silkworm breeds have probably changed, since modern silkworms have been bred for whiter, finer silk. Whether the new strings match those of the Tang (618–907) or the Song (960–1279), no one can say for certain. But they are made of silk, they sound husky, and the sliding finger is audible on them, all consistent with what earlier players described.

For a beginner

Steel. The reasons are given in the guide to starting the guqin (in Chinese): steel strings rarely break, hold their pitch and are cheap. What a beginner needs most is reliable intonation, and silk's drifting would interfere with training the ear. Beginners also break the most strings, and with steel that costs less.

Once your hands have a foundation and your ear knows what in tune means, try a set of silk. You will hear a different guqin: softer, huskier, closer, as if heard through a sheet of old paper. That is the sound players listened to for a thousand years, the sound of the thread the man in the workshop was twisting on his wheel. For how the instrument itself is made, see qin making.