Vietnamese scientists surmise that the concentration of stoves discovered recently at a major metallic archaeological site in Hanoi were used for making bronze items around 2,000 years ago.
The Dinh Trang site had been excavated six times before, most lately in 2008. It is one of two most important metallic sites in northern Vietnam, besides Dong Nau in Vinh Phuc Province.
"This is the seventh excavation at Dinh Trang and luckily, we discovered such a dense system of stoves," Lai Van Toi of the Vietnam Archaeology Institute was quoted by the news website Vietnamnet as saying Wednesday.
Scientists had followed pottery debris, bronze drum debris, bronze cinders and ash to find the stoves in an area of 300 square meters. The stoves were all the same, built in two parallel lines and in the direction that could facilitate wind power, scientists said. There a few stoves located outside the system.
"As there're that many stoves, they might not be normal stoves but those for casting metal," Toi said.
"The discovery of bronze cinder and debris of bronze drums further affirms the supposition that this place used to cast bronze."
Han Van Khan, history lecturer at Hanoi University of Social Sciences and Humanities, concurred.
Khan said too many stoves being put in such a small area cannot be household stoves. "They might have melted bronze."
And many people must have been operating the stoves at the same time to have enough bronze to cast a big item, he said.
It is not clear how many stoves have been found so far.
The latest excavation also found four graves that professor Nguyen Lan Cuong of the Vietnam Archaeology Institute said he will study further.
Toi said further digging at the site may reveal more stoves resembling modern ones that will help scientists visualize the life of ancient Vietnamese residents of the area.
But the task would be hard as the area scientists want to dig up belongs to the military.
Toi suggested the Ministry of Defense gives the area to the Hanoi Culture, Sports and Tourism Department, as it had done with the underground site of 1,000-year-old Thang Long Royal Citadel.
Dinh Trang was once the defense outpost for Co Loa, the kingdom built under An Duong Vuong in the 3rd century BC when the country was called Au Lac.
The site is important because it contains vestiges of different cultures from the bronze age to iron age, said Khan who has participated in several excavations of the area.
"Thus, Dinh Trang residents were surely the ones who directly built Co Loa," Khan was quoted by Saigon Tiep Thi as saying Wednesday.
The palace was known for a special spiral shape with nine curves.
Scientists have earlier found tombs and hundreds of weapons including knives, axes, spears and arrows.