Furthermore, some songs require the use of "雙音琴竹" (shuāng yīn qín zhǔ), literally "double-note yangqin hammers". These specially-constructed hammers have 2 striking surfaces, allowing the player to play up to 4 notes simultaneously (or even 8 notes, if the strings of the "left bridge" and "tenor bridge" are struck at a point where they intersect each other), resulting in a rich, powerful tone, which is especially pronounced in the lower registers due to the strings' long echoes. 林沖夜奔 (Lin Chong Flees In The Night), composed by 項祖華 (Xiang Zu Hua), is a representative solo piece which utilizes 雙音琴竹.