Qin Guan (Traditional Chinese: 秦觀; Simplified Chinese: 秦观) (1049 – c. 1100) was a Chinese writer and poet of the Song Dynasty. His courtesy name was Shaoyou (少游). Taixu was also his courtesy name. His pseudonym was Huaihai Jushi (淮海居士) and Hangou Jushi (邗沟居士). He was honored one of the four Bachelors of Sumen (苏门四学士) along with Huang Tingjian (黄庭坚)，Zhang Lei (张耒) and Chao Buzhi (晁补之). The style of his poetry-writing is subtle, graceful, and restrained; and he was famous for love-poem writing. His writing style of Ci, was classified into the Wanyue School, most works of which are subtle and concise. His talent was greatly appreciated by Su shi, one of the greatest poet in Song Dynasty. His most famous verse is "If love between both sides can last for age,why need they stay together night and day?" (两情若是久长时，又岂在朝朝暮暮？)He has a lot of other famous poets.
More Detail: http://en.wikipedia.org/wiki/Qin_Guan