The crime drama revolves around a cop-turned-security-guard Zhang Zili (played by Liao) investigating a series of grisly murders. All the victims seem to be connected to the charming yet melancholic Wu Zhizhen (played by Taiwanese actress Kwai Lun-mei) and Zhang falls for the femme fatale but is determined to solve the case, leading to an unexpected result.

It is set in the northeastern mainland city of Harbin and one of the questions that Diao is often asked - one which popped up again at a post-screening discussion during the HKIFF - is why did he cast a Taiwanese actress to play a northern native?

Diao responded that Fellini had used actors with Sicilian accents to play Roman characters, and it didn't affect their brilliance.

When asked about it again during our interview, he said: "Imitation is just a very basic concept [of acting]. If Kwai does a perfect northern accent, people's attention will shift to that, and then they'll neglect her inner performance."

Kwai spent days with a family in Harbin to learn the way they live and speak, Diao said, and she benefited from doing so. "To me, it is her understanding of the character and her sensibility that make her a good actress," he says.

is the third feature the 45-year-old Diao has directed. Neither of his previous efforts, in 2003 or in 2007, garnered that much attention from the mainland audience and media, even though had its world premiere at the Cannes Film Festival and was released in Europe. So, obscurity was familiar territory to him. Now he says he's noticed the pros and cons that come with fame.

"The good thing is that when your work gets recognition, you have a greater say and the power to get your message across to the audience," he says.

What's more, he believes the interviews he does help the public get to know him and his films better, as his work is the only way he gets to communicate to the world the fire inside him.

Another benefit is that fame also means his opinion carries greater weight. "On the street, anyone can shout. Your voice is one of many, and nobody cares what you say," Diao says. "But if you do your work properly and win people's respect, then you will have earned your say, and people will listen."

On the other hand, he says: "The bad thing is that your time and attention are restricted," as more demands are made on his schedule.

Diao grew up in Xian as a student of film, studying everything he could get his hands on. When asked who his major influences in filmmaking are, he cites Hungarian auteur Bela Tarr, who is known for a degree of abstraction.

Diao's award-winning third film has its share of abstraction too, in the form of various symbols and subtle details - such as a horse suddenly appearing in a house and the hysterical dance moves performed by Liao towards the finale. Diao is aware of the frustration these elements have caused among audience members, with many complaining they simply don't understand the film. But with the success of , critically and commercially, he is sure the film is paving a new road for other Chinese directors.

"Investors may not believe there are films that can balance commercial and artistic success, but this film is an example," he says.

Blazing this trail comes perfectly naturally to Diao. "Whether it is a film or a painting, your signature can be a bit hidden. But it is still there, just in a subtle way," he says of his artistic vision.

's Chinese title ( , which translates as "daytime fireworks", refers to the state of mind of the main characters in the film. It can also be read as a subtle metaphor for today's China, where unbelievable - or unimaginable - events happen, such as the crimes the film depicts. The contrast in the Chinese and English titles is also meant to reflect the difference between reality and dreams. As the director has stated: "Coal and ice are real; fireworks in daylight are surreal. They're two sides of the same coin."

Diao can be serious, even uptight, when he talks, but he has no hesitation when sharing his passion about filmmaking. Plainly and simply, for him, it is a dream-making process.

"But as a director I need to fend off unfavourable elements outside the dream for my cast and crew - for example, pressure from producers or the various difficulties we face," he says. "I need to protect my team and let them focus on the dreaming."

But now that has been made and screened in various territories, he wants to relax a bit. The director says he's not in a hurry to make his next film. He's not even reading what people think of his art. "If you want to stick to your own style, you don't need to listen to other people's opinions right away.

"All art is like that - not everyone will like it."

opens on May 15