When Cheng Shu Ren came to Vancouver from Shanghai 25 years ago, he wanted to learn about the history of the Chinese in Canada.

Two decades - and a lot of history - later (the Chinese have been in Canada since migrant workers helped to build the Canadian Pacific Railway line, in the 19th century), Cheng completed three murals charting the early history of Chinatown.

The first, 1884: Wah Chong Laundry, is a reproduction of a photograph taken just before a head tax of US$50 was imposed on Chinese arrivals in Canada, to deter immigration. The second is called 1905: Man in a Suit, and the third, 1936: Seated Men on Corner, shows smartly dressed Chinese men outside the Sam Kee building, which still stands.

Cheng says the murals represent times in Vancouver when the Chinese were under intense pressure from the government, and should serve as a reminder of how far society has come.

"Yes, there was racism in the past and it still exists to this day. But I believe we have all changed and it's not as bad as it was," Cheng says.

However, socioeconomic tensions, it seems, have returned to haunt the area.

Since being completed in 2010, the murals have been defaced a number of times. But this month saw the worst vandalism yet, with the 1905 piece being covered with scribbles.

Albert Fok, a Chinese herbalist and president of the Chinatown Business Improvement Association (BIA), says claims the graffiti was the result of racism are overreaching.

"It could be anyone who was drunk and wanted to cause mischief," he says.

Others believe the graffiti is a protest against gentrification.

Home to small businesses, the elderly and the poor for decades, Chinatown, due to its central location, has been transformed over the past 10 years. Developers have replaced old buildings with high-rise condominiums and trendy restaurants have sprung up in the area, helping to price the local Chinese residents out.

Vandalising a Chinese mural in protest against the dismantling of Chinatown may seem illogical, but that is what some believe has happened.

The BIA has paid for the murals to be restored and Cheng hopes history will serve as a deterrent to future vandalism.

"We must remember that when we look at those faces they are also looking back at us," he says. "We have to remember not to let those things happen again."