The koto is a traditional Japanese stringed musical instrument derived from the Chinese zither. The koto is the national instrument of Japan. Koto are about 180 centimetres long and have 13 strings that are strung over 13 movable bridges along the length of the instrument. Players can adjust the string pitches by moving these bridges before playing, and use three finger picks (on thumb, forefinger, and middle finger) to pluck the strings.
One of the characters for koto, is also read as sō in certain contexts. Though often called by a number of other names, these terms almost always refer to similar, but different instruments, such as the Chinese guzheng or guqin, called kin in Japanese.
The koto was first introduced to Japan in the 7th and 8th century from China. It originated in its earliest form in the 5th century. It was a very popular instrument in the Northeastern part of China. The first known version had five strings, which eventually progressed to seven strings. It had twelve strings when it was introduced to the China and increased to thirteen strings when it was introduced to Japan in the early Nara Period (710-784). This particular instrument is known throughout Asia but in different forms, the Japanese so or koto which is a distant relative to the qin, the Korean komungo, and the Vietnamese dan tranh. This variety of instrument came in two basic forms, a type that had bridges and those types without bridges. The type that was most known in China was the qin.
Originally, the word koto was a generic term for any and all Japanese string instruments when the so, or koto, was imported to Japan. Regardless, over time the definition of koto being all string could not describe the wide variety of these string instruments and the names were changed. The Azuma goto or yamato goto became the wagon, the kin no koto became the kin, and the sau no koto was changed to the so or koto.
