Bow (music)

In music, a bow is a stick which is strung with hair.  It is used to pull across the strings of a string instrument such as a violin, viola, cello or double bass.

Bow construction

The wood used for good quality bows is usually pernambuco wood from Brazil.  Some bows nowadays are made from carbon fiber.  They are often cheaper and still of very good quality.  The bow has to be slightly curved so that it straightens out a bit as the hairs are tightened (this is like the bow of ‘bow and arrow’ where letting go of the tension of the bent bow makes the arrow fly off). 

Horsehair is used for the hairs of the bow.  These hairs gradually fall out when the bow is used a lot.  When a lot of the hairs have fallen out the player can have the bow re-haired.  When the bow is new, or when it has just been re-haired, it will not make any sound until the hairs have been well rubbed with rosin (also called “colophony”).  The rosin makes the hair grip the string as it is drawn across.  Every violinist needs to keep a piece of rosin (called a “cake of rosin”) in his or her violin case.  They may need to rosin the bow for a short while each time they play.  There is a screw at the end of the bow for tightening the hairs.  After playing, the bow hairs should be slackened again before the bow is put away.  This is to stop the wood from warping (bending out of shape).

The black bit near the heel of the bow (the end where the player holds it) is called the frog.  This holds the hair in place.  The frog may be made of ebony, but sometimes it is made of ivory or tortoiseshell.  Near the frog is the grip, which is made of leather or sometimes snakeskin.  Expensive bows sometimes have a tip made of silver.

There are other instruments which use bows.  In the Renaissance the viols were played with a bow which was held with the palm upwards.  Some double bass players still hold the bow in this way (this is called the German method.  The overhand method is called the French method.)

The kind of bow in use today was developed by the bow-maker François Tourte in 19th century France.

There are other cultures which have bows with only one thick hair.

Bowing techniques

People who learn to play the violin, viola, violoncello, and double bass spend a very long time learning the technique of bowing.  They have to learn to control the bow so that it makes a lovely sound on the string.  They learn to control the bow with strong fingers, but never to hold the bow tightly.  Sometimes they are asked to pluck the string instead of bowing it.  This is called “pizzicato”.

The bow is held in the right hand.  The left hand makes the different notes by putting the fingers firmly down on the fingerboard.

When string players talk about “putting in the bowing” they mean: writing in the music for each note whether it is played with an upbow or downbow.   A downbow is when the player starts at the heel (the end that he is holding) and finishes at the tip.  An upbow is when the bow travels in the direction  tip to  heel.  A player does not always have to use “whole bows” (from the heel to the tip).  In fast music he may only use a small part of the bow.  A downbow feels stronger than an upbow, so it is usually used for the first beat of the bar.  Downbows and upbows may be used for alternate notes, but often two or more notes are taken in one bow-stroke.  This is shown in the music by a slur (a short curved line like a phrase mark over or under the notes to be slurred).

The bow generally should touch the part of the string mid-way between the end of the fingerboard and the bridge (see the article violin).  To play quietly the bow should be nearer the fingerboard.  To play loudly it should be nearer the bridge.

When the players have been plucking (pizzicato) and they need to start bowing again, the word arco is put in the music.  This is the Italian word for bow.

Special effects can be made with the bow.  These include: 
sul ponticello which means that the bow is playing towards the bridge.  This produces a glassy, stratching kind of sound, full of dissonant harmonics.  
Sul tasto means that the bow is over the fingerboard, producing a very quiet, muffled sound.
col legno (literally: with the wood) means that the players have to turn the bow over and hit the string with the wood.  Players with expensive bows often do not like doing this and bring a cheaper bow to play those bits.
On the string bowing means: keeping the bow in contact with the string between the notes.  
Off the string bowing means lifting or bouncing the bow.
Spiccato means making the bow bounce so that the notes are staccato (short and detached).
Ricochet bowing is making the bow bounce of its own accord very quickly in the upper half of the bow (near the tip).  Each bounce may be for a different note.  This is a very advanced technique.
Two strings can be played at once so that two notes sound.  This is called double stopping.
Three or four strings can be played at once, but only at very high dynamic levels and with a very loose bow - sometimes the effect of a chord is produced by double stopping quickly on two strings and then on the other two.

Other types of bow

The Chinese yazheng and yaqin, and Korean ajaeng zithers are generally played by "bowing" with a rosined stick, which rubs against the strings without any horsehair.  The hurdy-gurdy, an instrument known in medieval Europe, has strings which are bowed by a "rosin wheel," which is turned by a handle.

String instrument construction