HANGZHOU, Aug. 8 (Xinhua) -- Celebrating the Qixi festival, or traditional Chinese Valentine's Day, is much more than lovebirds' billing and cooing or sending gifts to woo love interests.

An exhibition of ancient books was held at the provincial Zhejiang Library in eastern China's Hangzhou City on Wednesday, passing on the old custom of insolating books during the festival.

Book lovers have feasted their eyes on precious classics like the "Siku Quanshu," China's largest encyclopedia on classic texts, history, philosophy and literature, which was compiled in the 18th century.

The custom has been known from as early as more than two millennia ago and was officially supported in the Song Dynasty (960-1279). Contemporaries, especially intellectuals, used to put their books in the sun to prevent them from becoming moldy on Qixi, a time known for its strong sunshine.

Unearthed Buddhist scripture and handwriting of famous local literati through the ages also met the public. Fifteen collectors were invited to the library to show their collections and tell their stories and feelings about the treasured books.

Founded in the early 20th century, Zhejiang Library is one of the oldest libraries in China, with a collection of more than 7 million books archived in five buildings, among which over 800,000 are old thread-bound ones.

Book-insolating activities were carried out across the province on this year's Qixi festival, according to the library, which is also the center for ancient books protection in Zhejiang.

Chen Yi, head of the rare book department at the library, said that such activities will help enhance people's understanding of ancient texts and improve their taste.