the score used. The second column was devoted to qin tablature. Western composers have noticed that the rhythm in a piece of qin music can change; once they seem to have got a beat, the beats change. This is due to the fact that qin players may use some free rhythm in their playing. Whatever beat they use will depend on the emotion or the feeling of the player, and how they interpret the piece. However, some melodies have sections of fixed rhythm which are played the same way generally. The main theme of Meihua Sannong, for example, uses this. Some sections of certain melodies require the player to play faster with force to express the emotion of the piece. Examples include the middle sections of Guangling San and Xiaoxiang Shuiyun. Other pieces, such as Jiu Kuang has a fixed rhythm throughout the entire piece. Organology While acoustics dictated the general form and construction of the guqin, its external form could and did take on a huge amount of variation, whether it be from the embellishments or even the basic structure of the instrument. Qin tablatures from the Song era onwards have catalogued a plethora of qin forms. All, however, obey very basic rules of acoustics and symbolism of form. The qin uses strings of silk or metal-nylon and is tuned in accordance to traditional principles. Ancient guqins were made of little more than wood and strings of twisted silk. Ornaments included inlaid dots of mother-of-pearl or other similar materials. Traditionally, the sound board was made of Chinese parasol wood firmiana simplex, its rounded shape symbolising the heavens. The bottom was made of Chinese Catalpa, Catalpa ovata, its flat shape symbolising earth. Modern instruments are most frequently made of Cunninghamia or other similar timbers. The traditional finish is of raw lacquer mixed with powdered deer horn, and the finishing process could take months of curing to complete. The finish develops cracks over time, and these cracks are believed to improve the instrument's sound as the wood and lacquer release tension. An antique guqin's age can be determined by this snake like crack pattern called "duanwen" (斷紋). Construction According to tradition, the qin originally had five strings, representing the five elements of metal, wood, water, fire and earth. Later, in the Zhou dynasty, Zhou Wen Wang added a sixth string to mourn his son, Boyikao. His successor, Zhou Wu Wang, added