Ning Hao's heist comedy "Crazy Stone" has emerged as the highest grossing local film in China so far this year, raking in more than RMB6 million in less than two weeks of release.

Distributed by Warner China Film HG, the surprise hit - a low budget HD film with no big stars - took RMB 2 million nationwide in its opening weekend. More impressively, its box office rose by 100% in its second weekend, defying the usual trend of box office revenues dropping off on the second weekend.

The picture, which opened on July 1, has benefited from its strategic release during the local film protection month (June 11 - July 10) when no revenue-sharing imported films were released. That no pirated DVDs were available in its first week also contributed to the box office success.

While "Crazy Stone" is written and directed by mainland Chinese film-maker Ning, it is produced by Hong Kong superstar Andy Lau's production company Focus Films as one of the six projects of the Focus: First Cuts series.

To help promote the film, Lau himself sings the theme song as well as appears in a poster, urging the audience to see "Crazy Stone" after the World Cup.

The picture is a black comedy centering around a group of bumbling thieves who have their eyes set on stealing a precious stone, which is discovered by a factory owner who wants to pay off his debt with the jewel.

The picture is scheduled to open in Hong Kong, Malaysia and Singapore in the coming months.