Koto is a Japanese
zither, about two metres in length. It has about a dozen silk
strings stretched across a wooden board. It has a moveable bridge, for raising
the pitch of a note. Strings are plucked with the fingers, or the player may
wear plectrums attached to their finger-nails.
The koto is usually
tuned to the pentatonic scale, which has only the 5 notes corresponding to our
western scale degrees of 1, 2, 3, 5, and 6. A 20-string koto can be tuned to the diatonic scale, thereby giving a range of 2 and a half octaves, with no chromatics. But all sorts of other tuning arrangements are possible.