The "crystal concordant" (perfectly harmonic) overtones can only be evoked by tapping the strings precisely at these hui. The third type is an yin (按音/案音, lit. "pressed sound"), which is sometimes also called shi yin (實音, lit. "full sound") or zou yin (走音, lit. "changing sound"). These comprise the major cadences of most qin pieces. To play an yin, the musician stops a string at a specific pitch on the board surface with the left thumb, middle or ring finger, strikes the string with the right hand, then they may slide the left hand up and down to vary the note. This technique is similar to playing a slide guitar across the player's lap. However, the manipulation of qin is much more multifarious than that of a guitar, which has only around 3 or 4 main techniques. (). According to the book Cunjian Guqin Zhifa Puzi Jilan, there are around 1,070 different finger techniques used for the qin. Thus the qin is possibly the instrument with the most playing techniques in both the Chinese and Western instrument families. Most of the qin's techniques are obsolete, but around 50 of them still appear in modern performance. Sometimes, guqin can be played with a violin bow. It has a tone similar to that of a cello, but raspier. The above four figures are from an old handbook. Tablature and notation Written qin music did not directly tell what notes were played; instead, it was written in a tablature detailing tuning, finger positions, and stroke technique, thus comprising a step by step method and description of how to play a piece. Some tablatures do indicate notes using the gongche system, or indicate rhythm using dots. The earliest example of the modern shorthand tablature survives from around the twelfth century CE. An earlier form of music notation from the Tang era survives in just one manuscript, dated to the seventh century CE, called Jieshi Diao Youlan (Solitary Orchid in Stone Tablet Mode). It is written in a longhand form called wenzi pu (文 字譜) (literally "written notation"), said to have been created by Yong Menzhou during the Warring States period, which gives all the details using ordinary written Chinese characters. Later in the Tang dynasty, Cao Rou and others simplified the notation, using only the important elements of the characters (like string number, plucking technique, hui number and which finger to stop the string)