Grinning widely, Mr Tran Quang Thieu brandishes the day's haul: 10kg of rats caught in rice paddies near Hanoi.
A menace to Vietnam's rice crop, the vermin are regularly trapped - and sometimes eaten.
In his village of Van Binh, on the outskirts of Hanoi, Mr Thieu and his team work night and day in the area's rice paddies. They estimate 20 per cent of the annual grain crop is lost to hungry rats.
Vietnam is the world's second-largest exporter of the staple grain.
"We used to have to accept the loss of large chunks of our paddies. The rats destroyed it," explains 46-year-old farmer Hoang Thi Tuyet.
"They're clever, they move fast and in Vietnam, there are 43 different species of rat to contend with," Mr Thieu told AFP.
But in 1998, he invented a new kind of rat trap, more effective than anything farmers had previously tried, that worked without bait and relied on extremely strong springs. He estimates his traps have killed millions of rats.
At least 500,000 hectares of rice paddy is lost to rats each year, out of about 7.5 million hectares planted across Vietnam, said Mr Nguyen Manh Hung of the Institute of Agricultural Sciences.
So it is no surprise that Mr Thieu - who is known as the "Rat King" for the trap that made him a fortune - is an extremely busy man.
NO TIME TO CATCH THEM ALL
"We get requests to come and catch rats from all over the country but we can't take them all up. We just don't have the time," he said.
His five children have all joined the family business and run six specialised companies.
Some 30 million of his special traps have been sold. And he does not just sell them to rice farmers - he has signed contracts to help hospitals, hotels, restaurants and schools to exterminate pests.
Rat-hunters can also sell their bounty to restaurants. Paddy rats are consumed in the country, from the Red River Delta in the north to the country's rice basket, the Mekong Delta, in the south.
"Rat meat is very oily, like suckling pig, and very rich in protein," said Mr Do Van Phong, sitting in a Hanoi restaurant with two large paddy rats on a plate in front of him.
The dish is popular in Vietnam but there are no official figures on how many restaurants serve it.
State media reports that between three and four tons of paddy rat a day is imported from neighbouring Cambodia for the restaurant trade.
According to Mr Phan Phan, a villager in Dinh Bang district in northern Bac Ninh province, rat meat has become a key part of local culture.
"It's a common dish, it's good to eat regularly, especially at family occasions, even weddings. People think it helps us to escape bad luck."
This article was first published on December 20, 2014.
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