It is more than 3,000 years old from the era of late Shang dynasty (11th – 10th century BC), and famous for its shape, each of the four sides of the belly has a big horn-curled goat.

It was unearthed in Huangcai Town, Ningxiang County in Hunan Province, and is exhibited at the National Museum of China.

The bottom is supported by ring feet (圈足支座) and the middle part was skillfully engraved with four goats with big curly horns.

When they first hoed it, they heard a crash, then a sheet of rusty copper about 10-centimetre (3.9 in) long and 8-centimetre (3.1 in) wide flew out of the soil.

They continued digging and a national treasure that had been sleeping soundly underground for more than 3,000 years gradually showed its magnificent appearance.

After Jiang Jingshu and his brothers unearthed the square zun, they didn't take it home until it was dark in order not to be found by others.

Zhao opened a cow leather shop on the surface but he secretly engaged in reselling antiques at a profit.

The owner of Wanlishan Shop offered a low price for such a valuable piece of art: 10,000 silver dollars.

So he consulted with the owner of Wanlishan Shop whether he could leave the square zun for him and he would go back to raise money at once.

In order to prevent the national treasure from being lost overseas and possibly destroyed, the government immediately sent police to investigate the matter and finally impounded the square zun.

The Cultural Relics Management Committee of Hunan sent expert Cai Jixiang (蔡季襄) and others to the scene.