Kong said it is important to get postmarks on the postcards to have a record of the places where he bought them.

In July 2002, he decided to fly to Lhasa in the Tibet autonomous region when he got a two-day break during a business trip to Chengdu. "When the officer at the post office learned that I went there just to buy postcards, he said he admired me and carefully postmarked all 50 postcards I bought that day," he said.

Kong said his age and health have prevented him from visiting Lhasa again.

"I feel quite proud to have visited all the provinces, autonomous regions, and municipalities in China, and to have seen the picturesque landscape of our country, as well as obtaining distinctive postcards," he said.

Kong has spent more than 10,000 yuan ($1,476) buying postcards over the years and devotes most of his spare time to his hobby.

"Luckily, I have received great support from my family members," he said. "And all my friends and relatives know my interest in collecting postcards and when they travel to other cities, they buy me postcards as presents.

"I enjoy immersing myself in the postcards as they record history and development. And I like to show them to the public, especially to the younger generations."

During the Beijing Olympic Games in August 2008, Kong held a postcard exhibition at a public exhibition hall near the National Stadium, known as the Bird's Nest, where the opening ceremony was held.

"I selected 2,008 postcards representing the wonderful landscapes in our country as well as various sports themes," Kong said. The two-day exhibition attracted many local residents as well as tourists from home and abroad.

"The visitors showed great interest in seeing the changes and development of China by comparing postcards from different periods," he said.

"I felt quite proud of my country and also enjoyed telling them interesting stories about the collection."

Less people choose postcards to express their wishes to friends or relatives nowadays, Kong said, but he will continue adding to the collection.

"In 2019, for the 70th anniversary of the founding of the People's Republic of China, I look forward to seeing a more wonderful set of postcards," he said.