The construction of the 13-string koto remains fundamentally the same for over 1,000 years. Paulownia is the best wood for constructing the body of the instrument to produces the distinctive sound and timbre. The standard dimensions of the 13-string koto are: 6 shaku (181.8 centimeters) in length, 25 centimeters in width, and 4.8 centimeters in height/thickness.

Traditionally, silk is used for the strings, ito. The techniques used in contemporary music, however, require an increased string tension and the durability of the strings. For this reason, the strings of synthetic materials are widely used at present.

The bridges of the koto are called ji or kotoji. The small bridges are used to tune a string when the correct pitch is impossible to obtain without being obstructed by a neighboring bridge.

A performer attaches three small picks called tsume to the thumb, index, and middle fingers of the right hand. They are made from ivory. The shape of the tsume differs depending on the school of performance. The Ikuta school uses square-shaped tsume, while the Yamada school uses a rounded tsume.

The koto is one of the traditional Japanese instruments. The present form of the 13-string koto originated from the instrument that came from China in the 7th and 8th centuries CE. It was originally used in gagaku court orchestras, and gradually spread to temples and commoners. Its popularisation is often attributed to Yatsuhashi Kengyo (1614-1685), a koto composer and educator. The koto developed into two distinct traditions, the Ikuta and the Yamada, which still remain the two major styles in Japan.

Historically, most pieces in the koto repertoire were vocal works with koto accompaniments. With influence of Western music since the Meiji era (1868-1912), koto player-composers such as Michio Miyagi (1894–1956) and Kinichi Nakanoshima (1904-1984) began a new movement of koto music. Miyagi not only composed over 300 works, but also invented the 17-string bass koto. By the 1960s, the koto welcomed its golden age. Many koto player-composers such as Tadao Sawai have furthered Miyagi’s vision to stretch the instrument in new directions. With integrity, creativity and determination of dedicated musicians, the koto continues to expand today.