SHANGHAI, March 2 (Xinhua) -- Salvage of a 160-year-old shipwreck, the largest and best-preserved wooden shipwreck discovered underwater in China to date, began Wednesday.

This sunken ship, with a large number of cultural relics, was a merchant vessel during the reign of Emperor Tongzhi (1862-1875) in the Qing Dynasty period.

Named Yangtze No. 2 Ancient Shipwreck, the ship was found submerged at a depth of 5.5 meters below the seabed in the waters of Hengsha shoal in the northeast of Hengsha island in Shanghai's Chongming District.

According to archaeological investigations, the ship is about 38.5 meters long and 7.8 meters at its widest in the middle. It has 31 cabins and is loaded with exquisite cultural relics such as porcelain made in Jingdezhen, a world-famous "porcelain capital" in east China's Jiangxi Province.

It is the first time in 15 years that China has carried out a large-scale underwater archaeological operation to salvage an ancient wooden shipwreck. The Southern Song Dynasty (1127-1279) ship "Nanhai No. 1" was raised out of water in December 2007.

"The Yangtze No.2 Ancient Shipwreck is a physical witness of Shanghai as a trade and shipping center of East Asia and even the world in modern times, as well as an important node of the Belt and Road," said Fang Shizhong, head of the Shanghai Municipal Administration of Cultural Heritage.

The salvage of the shipwreck is expected to be completed within this year.

Mysteries such as where the ship was from and headed for, why it sunk, what its real name was, how many cultural relics were loaded on the ship, and whether there will be more shipwrecks around the area are to be uncovered as archaeological work continues.