The shamisen is a member of the lute family. At its simplest, it is a square, skin-covered box (the dō) with a long, slender neck (the sao) protruding from that box, and three tuning pegs (itomaki) at the end of the neck. There are a number of different types of shamisen, depending on what genre of shamisen music one is playing. Each type has its own specs with regard to size of the dō, how far the skin is stretched on the dō, the neck thickness, size of the tuning pegs, etc. The skin used to cover the dō is commonly cat, dog, or synthetic, depending on the quality of the shamisen and on the genre of shamisen music being played.
The shamisen is generally classified in one of two ways, by
either its construction style or by its most commonly-played music. The
three best known and most played types of shamisen are:
Hoso-zao (literally: thin neck) - This is also called a nagauta shamisen, because of its use in the music of the Kabuki theatre. It is also used for other genres such as kouta, hauta, etc.
Chū-zao (literally: medium-sized neck) - This is also called a jiuta shamisen, since it is primarily used in jiuta music (solo, or as a duet with the koto part). It may be considered the most versatile of the three classes of shamisen, since it can easily be adapted for use in multiple genres of shamisen music.
Futo-zao (literally: thick neck) - This is also called a Tsugaru shamisen, because of its use in the popular folk music of the northern Tsugaru region. It may also be referred to as a gidayu shamisen, named for the music it plays in Bunraku puppet theatre. It has a big, bold sound compared to the other two types of shamisen, making it difficult to use this shamisen for the playing of other genres.
There are three main tunings in shamisen music. The starting pitch for the first string can vary depending upon which genre of shamisen music one is playing, upon school or teacher preferences, upon what instruments one is playing with, and so on. Therefore, rather than discussing the tunings using specific Western notes, it may be more practical to think of them in terms of positions in a scale. That way, one can easily adjust tunings up or down in pitch at will without needing to transpose (for instance, in order to accommodate a singer with a higher or lower vocal range).
The tunings are:
Hon-chōshi - This is the basic tuning from which the other two derive. Strings 1, 2 and 3 are tuned respectively to Do-Fa-Do, where Do is the first note of a major scale starting on any note you wish. (Intervals between strings are P4 and P5).
Ni-agari - The name literally means "raise 2". The tuning is made by raising the pitch of Hon-chōshi's string 2 by one tone, resulting in Do-So-Do. (Intervals between strings are P5 and P4.) Ni-agari tends to sound a little more cheerful or upbeat, compared to Hon-chōshi.
San-sagari - The name literally means "lower 3". The tuning is made by lowering the pitch of Hon-chōshi's string 3 by one tone, resulting Do-Fa-Ti flat. (Intervals between strings are P4 and P4). San-sagari sounds a little bit melancholic, compared to Hon-chōshi.
The shamisen's sound is produced by a bachi, or plectrum, held in the right hand. The bachi is shaped somewhat like an upside-down triangle mounted on a square stick. (Some people think it resembles an ice scraper.) It is the point of the upside-down triangle that strikes the strings to make the sound. The friction created by the string being pressed out between the bachi point and the shamisen's skin adds a "snap" which gives shamisen a distinctive sound. There are two main bachi techniques. The downward hit is the primary one, and there is also a lighter upstroke, where sound is produced using the point of the bachi to pluck the string from underneath. And in the kouta genre of shamisen music (a genre favoured by the geisha), the shamisen can be played without a bachi, using only the fingernail of the index finger to hit the strings. In all genres, the left hand is used to alter a string's pitch by pressing the string down against the neck with the index, middle or ring finger. The left hand is also used for ornamental effects, such as plucking or hitting the strings to produce the desired sound.
Introduction to Shamisen Kumiuta, Willem Adriaansz, Frits Knuf B.V.- Buren-The Netherlands
Japanese Musical Instruments: Images of Asia., Hugh DeFerranti, London: Oxford University Press.
The Spirit of Tsugaru: Blind Musicians, Tsugaru-jamisen, and the Folk Music of Northern Japan, Gerald Groemer, Harmonie Park Press.
Traditional Japanese Music and Musical Instruments, William P. Malm, Kodansha International.