The sho is a type of wind instrument used in gagaku (Court music in Japan). It is a free reed musical instrument. Similar instruments can be seen in many places in Eastern Asia. It is called the 'sheng' in Chinese.
It is thought to have been introduced to Japan along with gagaku around the Nara period.
The shape of sho used in gagaku is resembles a Chinese phoenix (hoo) resting with its wings aloft and for this reason is also called the 'hosho.'
17 thin bamboo pipes are arranged in a circle on a part known as the 'fukube.'
The player covers the finger holes along the bamboo pipes, inhales or exhales into the mouthpiece attached to the side of the fukube and the instrument produces a sound from the vibration of metal shita (reeds) which are attached to the bottom of 15 of the 17 pipes.
The key is determined by the natural oscillation of the shita, and the sound is created by resonating in the bamboo tubes. This is the same principle as the reed pipe of an organ. There are rectangular holes called byojo on several of the bamboo tubes, and their lengths as resonant tubes are determined by the locations of this holes, not by the entire length of the bamboo tubes. It is because of this that the apparent lengths of the bamboo tubes do not match their keys. Byojo can be on either the front or back of the instrument but decorated when on the front. The reason why no sound comes out of a tube where the finger hole has not been covered is because the finger holes are opened at locations where there is no resonance.
Unlike with a harmonica, inhaling or exhaling does not make any difference to the sound produced, and the player does not need to stop to take breaths as with another wind instruments, allowing a long period of uninterrupted play of the same sound (the volume of the sound is briefly lowered when the player switches his or her breath from inhaling to exhaling and vice versa). By changing the combination of holes covered, eleven chords called aitake can be produced. The instrument is usually played using the basic aitake but icchiku (playing melody with single sound) and special aitake are used in choshi, netori, saibara and roei performances.
The tone is said to express the light shining down from the sky.
Due to its structure, internal condensation from breath easily builds up and, if performed continually, water drops on the shita will distort the pitch and eventually lead to loss of sound. It is therefore necessary to warm the instrument using a brazier or stove before and in between performances.
Today, the instrument is not only used in gagaku, but also used by classical music composers in orchestral music and chamber music, or as accompaniment for vocal music.
There is also an instrument called an 'u,' which produces a sound one octave lower than a sho. This instrument disappeared from gagaku tradition but was restored after World War II by referring to the treasures in the Shosoin Treasure House. It is used in revived classics as well as newly composed modern gagaku music such as 'Showa Tempyoraku' by Toshiro MAYUZUMI.
There is an instrument in China called the 'sheng' in Mandarin and 'san' in Cantonese that is written using the same character as 'sho.'
It is larger than the Japanese sho, has more than twice its range and can respond to rapid movements. When first introduced to Japan during the Nara period, the Japanese sho also had a pipe-like mouthpiece but this has since been removed and the instrument is now played by placing the mouth directly on the body.
There is an instrument from Laos and the Northeastern part of Thailand called the khene that works according to the same principle and one theory states that this is the predecessor of the Chinese sheng.
Order of Bamboo Tubes
The key has no relationship to the length of the bamboo tube, and the following are listed in clockwise order from the right a viewed from the mouthpiece.
Ya and mo are silent in modern sho because they do not contain a reeds.