Photographs Chen took to mark the unexpected reunion show him crying tears of joy and also relief.

"I don't know if I was crying or smiling. I was so excited. Stray dogs are often captured and killed in Beijing."

Chen is certain that the dog he claimed on Feb 6 was Benben. "I'm the owner. I knew that's my dog when I saw it. Benben's tail and paws are white."

Benben's condition, considering her ordeal, is surprisingly good.

"She hasn't changed much, except for getting thinner. Now she is a little slow and doesn't run so much as before."

Seven years later, some habits have changed as Benben became streetwise and had to fend for herself.

"She used to be very picky with food. Now she eats almost anything, and scavenges food from trash heaps."

And she is more timid. Chen recalled when Benben bolted away at the sight of reporters carrying a camera and refused to return no matter how many times Chen whistled and called her name.

"She's afraid of people, especially when they hold something in their hands She lets nobody near except me and my parents."

Chen has received a large number of online comments.

A micro blog user going by the moniker of Zhuziqing said: "I have a dog. I know the feeling between man and dog. I cried when I saw you and Benben got together again."

But there are criticisms too, especially for not having Benben on a leash seven years ago.

Ostreich, another micro blog user, said: "Walking an unchained pet dog in the city not only frightens other people but also makes it more likely that dogfights will occur. It's your fault for not putting your dog on a leash."

A regulation on dog management in Beijing, which took effect in 2003, stipulates that people should put a leash on their dogs in public.

Xu Dongsheng, deputy secretary-general of Beijing Kennel Club, said it takes time for dogs to get rid of habits formed after they strayed.