The Palace Museum in Beijing has opened a major exhibition showcasing 107 Chinese calligraphy and painting masterpieces dating from the 7th to the 13th century.   Titled "Defining the Classics: A Journey to Tang and Song Calligraphy and Paintings", the exhibition runs through November 1 at Wenhua Hall in the Forbidden City. It features 103 works from the museum’s collection and four loans from museums in Shanghai, Shanxi and Henan.   Spanning calligraphy, landscapes, figures and bird-and-flower paintings, the exhibition explores how artists across the Tang, Five Dynasties and Song periods drew on earlier traditions while developing new artistic approaches.   Highlights include a Song Dynasty copy of "The Nymph of the Luo River", Yan Liben’s "Emperor Taizong Receiving the Tibetan Envoy", which returns after three years of conservation, and the silk painting "Fuxi and Nvwa", displayed publicly for the first time in nearly 30 years.   The exhibition will rotate on September 30, with Song Dynasty works taking the spotlight through November 1.