Liu said many of the Chinese participants have gone on to get jobs related to tourism, international trade and foreign affairs, important sectors for Guilin. Official data show the city received 38.7 million visitors last year, including 2 million from overseas.

The retired teacher also regularly receives letters from Chinese and foreigners, both residents and tourists, thanking him for his hard work and commitment in running the English corner.

A former Chinese student who later moved to live in Canada wrote: "Over several years it helped me improve my oral English from a tongue-tied person to a fluent English speaker."

Liu also keeps a guest book for people who take part to sign. Inside, one British tourist called Marry said she first visited Guilin 15 years ago and came across the English corner by chance. Since then, she has retuned every year.

Another traveler, Bill from the United States, described the English corner as "like a family" that has enabled him to learn about Guilin and its people, and to fall in love with Chinese culture.

Liu said that in 2011 a Norwegian tourist called David donated his life savings - about 230,000 yuan ($36,000) - to help poor students he had met at the English corner before dying of lung cancer aged 84. The man had stayed in Guilin a few months every year between 2003 and 2010 and regularly took part in the classes.

The money was used to establish a fund, supervised by three trustees, to cover the costs of the English corner and support students from poor families.

Another entry in the guest book is Craig Keller, an American tourist, who wrote: "I made many friends at the English corner in Guilin. I see it as my home in China."