The shamisen is a remodeled version of the snake-skin covered sanshin or jabisen which came to Japan from the Ryukyu islands in the Muromachi period. In ancient Egypt there was a three-string skin-covered instrument called the "nefer" or "nofer." This developed into the three-string setaru in Persia (present day Iran). In the language of Iran, "se" means "three" and "taru" means "strings," making the meaning the same as the word "sanshin." In Yuan dynasty China, a snake-skin covered three-string instrument was developed and around 1390, this instrument was introduced into the Ryukyu kingdom from China. This was during the Ming dynasty and it is said that the instrument was brought to the Ryukyus by people from the Konan province in China.
Some one hundred years later, a great genius in the Ryukyus named Akainko improved the instrument and composed many pieces, establishing the foundation of Ryukyu sanshin music. Around 1562, the instrument was introduced into Japan by trade ships. At that time, the instrument entered into two geographical areas, in Kansai, in the cities of Sakai and Osaka and in the port of Hakata in Kyushu. In Kyushu, the instrument was played by blind priests.
Since snakeskin is hard to get in Japan, in Sakai the instrument was covered with either dog or cat skin. After some thirty years of experiments and improvements, by the beginning of the Azuchi period, the basic shape of the modern shamisen was established.
The oldest shamisen in existence today is called Yodo and was made by an artisan in Kyoto on the orders of Toyotomi Hideyoshi.
Although in the early days of kabuki the music ensemble was virtually identical to the Noh ensemble with no shamisen, soon the shamisen became an indispensable part of kabuki and of almost all music in the Edo period. There are several different types of shamisen, with different types of plectrums and bridges to create a wide range of sounds in a very wide range of different styles of music.

The shamisen is made of two wooden parts, the body of the instrument or "do" which is a square box that is covered with skin on either side and the neck or "sao." The sao flares out at the upper end and this top part is called the "tenjin," then there is an opening for the ends of the pegs where the strings are wrapped and a strip of metal that serves as the upper bridge for the strings. A kind of buzzing sound is an important part of the resonance of the instrument and often, some kind of device is put into the upper neck to emphasize this sound. Then the bottom end of the sao goes through the do and sticks out slightly on the other end. The ends of the strings are tied to a brocade knot which is then looped around the end of the sao.
The most prized wood for the shamisen is koki, a very hard imported kind of rosewood, but rosewood, walnut and mulberry are also used. The sao is 62.5 cm. long, but there are different thicknesses depending on the type of shamisen. The three basic types are "hosozao" or "narrow neck," which is used for Nagauta, "chuzao" or "middle-sized neck," which is used for Tokiwazu, Kiyomoto and Shinnai, and "futozao" or "thick necked," which is used for Gidayu. The sao is made from one piece of wood, but often it is divided into two or three pieces so that it can be disassembled to be carried compactly.
The do is made from Chinese quince, mulberry or zelkova wood. A kind of cover made of cardboard covered with cloth is placed on the upper side of the do and the player rests his right forearm on this cover. The do is covered with skin front and back. Either cat skin or dog skin is used but recently, plastic skins are also sometimes used.
The strings are made of silk and are numbered from top to bottom. "Ichi no ito" or the "first string," is on the left or top side of the sao and is the thickest and lowest in pitch. "Ni no ito" or the "second string," is thinner and higher in pitch. "San no ito" or the "third string," is the thinnest and highest in pitch and is also the string that is used the most. Although virtually all the parts of the shamisen are made from imported materials, the strings are all produced in Japan, the raw silk and strings coming from places on the northern shore of Lake Biwa in Shiga Prefecture. One san no ito is made by taking the basic thread, which is made by twisting seven of the threads directly from the silkworm cocoon and then twisting forty of these basic threads together. Then a ni no ito is made by twisting two san no ito together and an ichi no ito is made by twisting three san no ito together. Silk strings are almost exclusively used, but there are also nylon strings.
A bridge or "koma" is placed on the skin and transfers the vibrations of the strings to the skins which amplify the sound. There are many different types of koma of different heights, widths, material and weights. Koma can be made from ivory, water buffalo horn, whalebone, bamboo, rosewood and ebony. The type of koma differs with the genre of music and the type of shamisen sound that is featured by that genre. Gidayu and Jiuta often use water buffalo horn, while Nagauta often uses ivory. On occasion lead is also put into the bridge to create a deep heavy sound. Other koma are made to emphasize think bright sounds.
The instrument is played with a plectrum or "bachi." The player grips a square rod which opens out in a fan shape and the strings are played with the thin edges of the plectrum. There are many different shapes, weights and materials for different genres. Jiuta uses water buffalo horn, Nagauta uses ivory and Gidayu uses both. Horn is valued for great hardness and flexibility, ivory combines great strength and softness. In addition, ivory is greatly prized for the grip since it absorbs moisture and soaks up sweat, so that the plectrum does not become slippery as the player sweats during a performance.

There are three basic tunings. First there is "honchoshi" or "main tuning," with the second string tuned a fourth above the first string and the third string an octave above. Then there is "ni agari" or "raising the second string" with the second string tuned a step higher, and "san sagari" or "lowering the third string," with the third string tuned a step lower. Each tuning has a slightly different feeling and pieces are in different tunings to reflect the atmosphere of a piece, to express the differences between genres and to add variety to a piece. In addition to these basic tunings, there are other tunings that are used on rare occasions.
The player sits in the seiza formal kneeling position and rests the do on his right leg and holds the instrument in place with his right arm. Then the sao is held with the left hand. The plectrum is held in the right hand and plays with forceful strokes that not only pluck the strings but hit the skin or wood of the body of the instrument to produce a percussive sound. The string can also be played by plucking upward with the plectrum. The left hand presses down on the strings with the fingernails of the forefinger, middle finger and ring finger. On occasion the player can pluck the strings with the fingers of the left hand. Also, in general, the relatively intimate Kouta style usually does not use a plectrum. The player plucks the strings with the fingernails of the right hand, a style that is called "tsume biki (playing with the fingernails)."