Early History
The Pipa (琵琶) is a 4-stringed lute with nearly 2,000 years of history in China. The instrument first appeared in China during the Wei dynasty (386-534 C.E.), introduced along ancient trade routes connected with Central and West Asia. It is a relative of the Arabic Oud, an ancient pear-shaped lute, and it is the predecessor of the Japanese Biwa, the Vietnamese dan ty ba, and the now obsolete Korean Bipa.
The two characters, pi (琵) and pa (琶), originally referred to two finger techniques, pi (琵) “to play forward,” and pa (琶) “to play backward.” It is also known that Pipa (琵琶) used to refer to any plucked string instrument of ancient times. The Xiantao, a plucked instrument that dates back to the Qin Dynasty (222-207 B.C.), is considered to be one of Pipa’s predecessors. It features a round body and a straight neck.
By the Han Dynasty (206 B.C.-220 C.E.), the instrument became known as the Qin Pipa (秦琵琶) and it featured 4 strings and 12 frets. In the Western Jin Dynasty (256-316), the Qin Pipa was named after a great scholar, Ruan Xian, who was one of the “Seven Sages of Bamboo Grove.” Due to his great mastery on the instrument, it has become known as Ruan while the Pipa referred to a new version in the same family of instruments.
During the Northern and Southern Dynasty (420-589 C.E.), a plucked string instrument called the Oud or barbat, arrived via the Silk Road. This instrument became known as the Hu Pipa, hu meaning foreign in Chinese. During the Tang Dynasty (618-907), foreign music was appreciated and adopted by the royal court. A fusion of the earlier string instruments with the foreign Oud eventually lead to the Tang Pipa.

The Tang Pipa originally was played horizontally and plucked by using a large wooden plectrum. The Japanese Biwa. descendant of the the Pipa, still maintains this position and playing technique. The Tang Pipa was larger than the modern Pipa, had 4 or 5 silk strings, and less frets. During the mid-Tang and Song dynasties (960-1279), the fingernails were used to play the instrument in an upright position.

Pipa players from the Nanguan style, popular to the southern province of Fujian and Taiwan, play the instrument horizontally and with a small plectrum. It should also be noted that the Nanguan Pipa maintains the earlier pentatonic system of frets and is generally a dark blue color, similar to early the Tang Pipa.
Modern Pipa

Surprisingly enough, the Pipa, an instrument with many centuries of history, has only evolved into its modern form during the 20th century. Three major innovations made in the 20th century distinguish the modern instrument from its ancestor.
The first and most significant innovation was regarding the tuning system. Prior to the 20th century, the frets on the Pipa were arranged for a pentatonic scale. This meant the intervals, or spaces, between frets were longer or shorter than each other. The instrument was also limited to play only in a few keys.
In the 1920s, Liu Tianhua (刘天华), Pipa and Erhu virtuoso, experimented with new designs that would revolutionize the instrument. Liu Tianhua is credited with inventing the chromatic pipa. He increased the number of frets ( 2 on the neck and 5 on the body) and arranged the notes for a chromatic (12-note) scale. This resulted in a Pipa with equal temperament, a system of tuning in which every pitch is separated by the same interval. The chromatic pipa could now be in all 12 keys making it suitable for playing both Chinese and Western repertoires. It was not until the 1950s, that his experiments were further developed and his innovative designs lead to a standardized, modern version.
The second innovation lead to a drastic transformation in the Pipa’s playing style and sound. Pipa players eventually started wearing fake nails, often made of turtle shell or plastic, fastened to the fingers with cloth tape. The nails offered greater volume and attack. The nails also allowed players to develop new techniques leading to an evolution of playing style.
The third innovation replaced traditional silk strings, that were low in volume, with nylon-wound metal strings. The metal strings were much louder and had a brighter sound than the silk strings. The switch to metal strings, along with the use of fake nails enhanced the power and the musical expression of the instrument.