Tsang’s work aside, these all have commercial interests at heart – Yim is looking for more customers, and HKwalls is backed by shoe company Vans – which is just about the opposite of everything graffiti stands for.

While there are examples of graffiti going as far back as ancient Egypt and Rome, the contemporary version dates to the 1970s, when it flourished as part of the hip-hop subculture in African-American neighbourhoods in New York.

Fred Brathwaite, one of the earliest graffiti artists in New York, told the Post in 2013 that he and other African-American youths turned to the streets because they had nowhere else to go: “I was always interested in art, but black kids like myself weren’t exactly getting a lot of opportunities at art galleries in the ’70s.”

MC Yan (Chan Kwong-yan), seminal Hong Kong rapper and a friend of Brathwaite’s, says graffiti was developed as a voice for the oppressed. However, he says, “what we see in Hong Kong [today] is not graffiti, but commercialised projects”.

That’s not to say the works of HKwalls or Yim have no artistic merit. But given the origins of hip hop and graffiti, it’s perhaps more apt to call them “street art” instead.

Which begs the questions: why isn’t Hong Kong a centre of graffiti like so many other cities around teh world?

Yumoh, 25, one of only a few full-time “taggers” in town, estimates there to be only around 10 graffiti artists in Hong Kong, including part-timers.

­

“A lot of people say they’re graffiti artists but they paint only once every six months,” he says. “There are a lot of tourists who come through to Hong Kong [to paint].”

Yumoh is his tag, not his real name. He knows his work is illegal – after all, he’s been taken into custody by police three times – so he prefers to stay anonymous.

“The first time it was with two other friends and we were just painting some stores near Central, you know, those ones that sell Halloween costumes [on Pottinger Lane],” he says.

“I had a feeling it was a little too hot, too many people around, but my friend said it was all right. So we painted some bubble letters, what we call throw-ups, and after we were done we walked around the corner and saw some police.”

This small group is responsible for most of the graffiti in Sheung Wan – especially in Po Hing Fong and along Hollywood Road – which regularly attract visitors and tourists. There’s also the “CY Xia Tai” (CY Leung Step Down) slogans sprayed on several hiking trails, although the artist behind those is a mystery.

Still, this subculture is minuscule in Hong Kong compared to most other major metropolises.

For example, while it’s not unusual to find graffiti on subways and rail systems throughout Europe and the United States, the MTR remains virtually graffiti-free – as if each train only started running yesterday.

The MTR would like you to believe it’s because it is very much on the ball.

“Train compartments and stations are cleaned daily, and MTR staff regularly patrol the premises, and ...we strive to quickly remove and repair any damage,” says a spokesman for the MTR.

The reality is that there’s not much art for them to scrub away to begin with. The consensus among street artists – both legal and illegal – is that the number of taggers is so small, the MTR encounters maybe one or two incidents a year.

Graffiti just never caught on in the city, says Stan Wu, director of HKwalls.

“It always has been pretty minimal – it’s the same people doing it over and over again,” Wu says, referring to local taggers. Still, he says, “Hong Kong is a big city, and there are people coming through that would paint. I’d say the scene here is half visitors, half locals.”

Wu says he began painting in 2001, at the age of 16, when he took an interest in British graffiti artist Banksy.

“Banksy was going on and people started doing it in Hong Kong, but the wave passed and no one sustained it,” he says. “Now this festival will hit the surface for a bit and then disappear. Stuff never took root out here.”

But why wouldn’t graffiti take off in a diverse, Westernised international city such as Hong Kong?

Artists involved in the small local scene attribute the lack of interest to a number of things – Wu says Hongkongers in general have quite eclectic interests.

“Today it will be manga, tomorrow it might be a video game or it might be fishing,” he says. “People just change so quickly to different culture and different interest groups. It makes them less interested in one thing.”

Yumoh, who began painting walls when he was 16, believes Hongkongers don’t spray paint because they innately don’t want to break the law.

“People in Hong Kong have grown up to kind of respect nature, to respect elders and, yes, there is a lack of rebelliousness,” he says. “I’ve had people ask me, ‘Why do you do it? Didn’t your parents teach you not to write on stuff, not to get arrested, not to do anything that’s against the law?”

Gary Wong Pui-fung, a sociology lecturer at the University of Hong Kong, says Hongkongers tend to relate graffiti to crime and disorder.

“It’s not a kind of art that is agreeable to society ... to many people art is something in a museum or endorsed by a kind of authority,” he says.

Even for those who decide to paint without permission, the penalty is generally not too harsh, Wu says.

“I think the police are super chill when it comes to graffiti,” he says. “Just in the last two weeks my friend got stopped by the police for painting and didn’t even go to the police station.”

Chan, who used to tag regularly around Asia – most famously on the Great Wall of China – says Hongkongers don’t quite understand the true meaning of art.

“Art is about an expression of ideas, not something that’s done to solely make money,” he says. “I don’t think our culture nourishes freedom of expression. Whenever youths develop a subculture that’s rebellious or independent, schools and teachers try to shut it down right away.”

While Chan takes a critical view of commercialised street art, others argue it is not so black and white.

“I know ideally, art shouldn’t be commercial, but artists still have to eat,” says Bao Ho, the 27-year-old street artist whose colourful murals can be seen in Sai Ying Pun and Sheung Wan.

Ho started out doing illicit graffiti, but ever since she won a street art competition last summer, her services have been in demand by establishments such as Mana Cafe and Starbucks.

“The key is to find a balance,” she says. “I make a living doing street art now, but the companies that pay me still let me keep my creativity and paint what I want. That’s the most important thing – I just want to create art.”