The satsuma-biwa is a pear-shaped lute. Its body consists of two pieces of wood (the frontal one is slightly curved) which are glued together, leaving a narrow air chamber. Three acoustic holes are drilled into the sound-board, two of which are camouflaged by moon-shaped ivory or silver plates, while the third is located under the bridge, the instrument is usually made of hard mulberry wood, which allows the player to use the bachi (plectrum) to strike the body. The neck of the biwa is bent 90 degrees backwards, which gives the instrument its characteristic "crane neck".
The gen or ito (strings)
The five (the top strings are double, originally four) biwa strings are made of silk fibres plied together with rice paste. They are tied to the bridge by a special knot, then tightened with the help of a tuning peg. They are tuned in a pitch chosen by the performer according to his/her voice register. Melody-lines are played on the thin double top-string. The bottom-string, usually used as an open-string drone, is the thickest.
The chû (pillars or frets)
Placed on the strings and in-between the chû, the fingers of the left hand control the tension of the strings. the five chû are extremely high and wide. Width is necessary for the special buzzing effect called sawari (a similar effect is known from the South Indian vina), while height allows for controlling and varying the tension by pulling, pressing or loosing the strings, in this manner, the pitch of the strings can be constantly modified.
The bachi (plectrum)
The strings are plucked with the sharp top edge of the triangular bachi which is held in the right hand. The bachi allows to produce a wide variety of dynamics and timbres, as well as arpeggios and scraping effects. likewise, the bachi may de used to strike the body of the biwa. The fan-shaped bachi of the satsuma-biwa is the largest plectrum in biwa music. to make a bachi, it is preferable to use the rare boxwood from Ibusuki (in Kyûshû) which should dry for more than ten years to possess both hardness and flexibility.
The Biwa Vocab
For in-depth information about the satsuma-biwa, you may visit the website Biwa Vocab - satsuma-biwa sound information system created by Junko Ueda.