The erhu is a two-stringed bowed instrument central to Chinese traditional and classical music, often described by listeners as sounding remarkably close to a human singing voice. Unlike bowed instruments with a fingerboard, the erhu's strings run freely above an open neck, and its bow passes between rather than over its two strings, producing a playing mechanism that is genuinely different from Western bowed string instruments. This guide explains how the erhu is built, how its unusual bowing works, and what gives the instrument its expressive, voice-like character.
Key Ideas
- The erhu has only two strings and no fingerboard, so the left hand presses strings in the open air rather than against a solid surface.
- Its bow hair passes between the two strings rather than over them, meaning the player plays one string by pushing the bow and the other by pulling it in a continuous motion.
- A small resonator, traditionally covered on one side with python skin, sits at the base of the instrument and shapes much of its tone.
- The absence of a fingerboard allows continuous sliding and vibrato that contribute to the erhu's often voice-like, expressive sound.
- The erhu is central to Chinese traditional and contemporary orchestral music and is generally learned over a sustained period with a teacher.
Place in Chinese Musical Tradition
The erhu belongs to a broader family of Chinese bowed instruments known as huqin, and many sources describe its general lineage as connected to bowed instruments that spread across parts of Central and East Asia over several centuries, though exact historical details and dates vary between sources and are often presented as general patterns rather than fixed facts. The erhu became especially prominent in regional opera accompaniment and folk ensembles, and over the twentieth century it also became a featured solo and orchestral instrument within modern Chinese orchestras, where it is frequently given melodic lines in a role sometimes compared, loosely, to the way a violin leads a Western string section, though the comparison only goes so far given how differently the two instruments are built and played.
Basic Construction
An erhu consists of a long, thin neck topped with two tuning pegs, attached to a small hexagonal or sometimes octagonal resonator body at the bottom. One face of this resonator is traditionally covered with a stretched membrane, most often python skin in traditional instruments, while the back is typically left open or covered with a fitted wooden or carved cover. Crucially, the neck has no fingerboard and no frets; the two strings run essentially in open air above the neck for most of their length, anchored near the top by the pegs and near the bottom by the resonator. This is a fundamental structural difference from Western bowed instruments like the cello or violin, where the strings are pressed down firmly against a solid wooden fingerboard.
Two Strings, No Fingerboard
Because there is no fingerboard to press against, the left-hand fingers stop the strings by pressing them against each other or simply shortening the vibrating length through controlled finger pressure in open space, rather than pushing a string down onto a hard surface. This takes a different kind of finger control than fingerboard instruments require, and it also makes continuous pitch sliding and wide, singing vibrato particularly natural on the erhu, since there is no fixed surface interrupting the string's movement. The two strings are typically tuned a fifth apart, and because there are only two, the instrument's melodic range per string is comparatively limited, which shapes much of how erhu repertoire is composed and performed.
The Bow Between the Strings
Perhaps the most distinctive mechanical feature of the erhu is that the bow hair passes between the two strings rather than over the top of them, as it would on a violin or cello. This means a single bow stroke direction naturally favors one string, and the player moves the bow at a slight angle, or adjusts pressure and angle with the wrist, to shift which string is sounding, all without lifting the bow away from the instrument. This "bow between the strings" design, shared by other members of the huqin family, is one of the clearest and most reliable ways to visually identify the erhu and its relatives when watching a performance, distinguishing it immediately from Western bowed instruments.
Tone and the Resonator
The erhu's small, membrane-covered resonator plays a large role in its characteristic nasal, singing tone, which many listeners describe as close to a human voice, particularly in slower, expressive passages. The size and tension of the membrane, along with the resonator's shape and the wood used in its construction, all affect tone color and volume, and professional players and instrument makers often pay close attention to matching a resonator's qualities to the player's style. Compared to the thicker, fully wooden soundboard of a Western string instrument, the membrane-covered resonator gives the erhu a brighter, more immediately vocal quality. Readers curious about how bow pressure, speed, and contact point shape tone more generally may want to review how bows affect the sound of string instruments, since many of the same general principles apply across bowed traditions even when the mechanics differ.
Key Terms
- Huqin
- The broader family of Chinese bowed string instruments to which the erhu belongs.
- Resonator
- The small hexagonal or octagonal body, often covered with python skin, that projects the erhu's sound.
- Open-string fingering
- The technique of stopping pitches without a fingerboard, by pressing fingers against the strings in open air.
- Bow-between-strings design
- The construction in which the bow hair passes between, rather than over, the instrument's two strings.
- Vibrato
- A controlled wavering of pitch, especially natural on the erhu due to its lack of a fingerboard.
Common Misconceptions
A common misconception is that the erhu is simply "a Chinese violin." While both are bowed string instruments, the erhu has only two strings, no fingerboard, and a bow that passes between the strings rather than over them, making its playing mechanics genuinely distinct rather than a regional variant of the violin. Another misconception assumes the erhu's voice-like sound is primarily a matter of playing style; in fact, the membrane-covered resonator and the open, fingerboard-free strings both contribute structurally to that quality, independent of any individual player's technique. A third misconception treats all huqin-family instruments as interchangeable with the erhu; in reality, the huqin family includes several related but distinct instruments with their own sizes, tunings, and regional associations.
What to Listen For
Listen for smooth, continuous slides between pitches rather than clean steps, which reflect the lack of a fingerboard and are central to the instrument's expressive style. Notice the nasal, voice-like tone quality, especially in slow, lyrical passages, which often draws direct comparisons to a singer. Pay attention to how a melody can move between the two strings without an audible break, a result of the bow-between-strings mechanism rather than separate bow strokes for each string. In ensemble or orchestral recordings, listen for the erhu frequently carrying a prominent melodic line, often doubled or answered by other instruments in the ensemble.
Getting Started
Because the erhu requires precise left-hand finger pressure without the support of a fingerboard, along with coordinated bow control between two strings, it is widely considered a demanding instrument to begin, and most guidance recommends starting with a qualified teacher who can correct hand position and bow angle early on. Beginners typically spend considerable early practice time simply developing a stable, even bow stroke and accurate finger pressure before attempting melodic repertoire. Those new to bowed string instruments in general may want to first review basic bowing techniques explained for foundational concepts that carry over, with adjustments, to the erhu.
Erhu Compared to the Violin
| Feature | Erhu | Violin |
|---|---|---|
| Number of strings | Two | Four |
| Fingerboard | None; strings run in open air | Solid fingerboard |
| Bow mechanism | Bow hair passes between the two strings | Bow hair passes over the strings |
| Resonating body | Small membrane-covered resonator | Full wooden soundbox |
| Playing position | Resonator often rests on the player's leg, instrument held upright | Held under the chin and against the shoulder |
Frequently Asked Questions
Why does the erhu only have two strings?
The two-string design is a defining historical feature of the instrument and its huqin family relatives; melodic range and technique are built around this limitation rather than around a four- or five-string layout.
How does the bow play two strings without a fingerboard?
The bow hair passes between the two strings, so a given stroke direction naturally favors one string, and the player shifts bow angle and pressure to move between them without lifting the bow away.
Why does the erhu sound like a human voice?
Its lack of a fingerboard allows continuous sliding and vibrato, and its membrane-covered resonator produces a bright, vocal-like tone, both of which contribute to the frequent comparison to singing.
Is the erhu hard to learn for someone coming from violin?
Prior bowing experience can help with general bow control, but the erhu's fingerboard-free left hand and between-the-strings bowing are different enough that most violinists still need dedicated instruction to adapt.
- Grove Music Online
- The New Grove Dictionary of Musical Instruments
- Smithsonian Institution, National Museum of American History