The dark side of the triads. The best film ever made on this topic, nothing less. 
Wong Jing is mostly famous for his innumerable lousy films all more commercial than the others ; that's why it's easy to spit on this "fat guy" of the Hong-Kong cinema. Nonetheless, for those who knows him better, he's also the creator
of gambling movies through the worshiped To San, God Of Gamblers, the director of a few fair Jet Li's films (particularly the parody Claws Of Steel) and most of all, the one who launched Andy Lau's cinematographic career wich explains his presence in much of Jing's mediocrities, including recent ones (The Wesley's Mysterious Files...geez !).
Seating in the chair wich's his, I just can't believe that Jing has never had any kind of link to the triads (even the convenience store owner at the corner of the street bumps into triads, so...) and it's probably his true opinion on them that he gives us in A True Mob Story.
The title is pretty unequivocal for that matter : "A True Mob Story", wich is exactly what the movie represents.
You follow Cheung-Dee, magnificently portrayed by Andy Lau, local small potatoe who sorely tries to assert himself among his family.
Forget everything that you might've seen before, forget all those big-hearted mobsters, full of principles, ready to rescue women and childrens (the exact opposite of movies like Young And Dangerous but people like John Woo, Chow Yun-Fat or Ti Lung are also targeted).
The topic here is reality, triads are criminals, culturally ingrained and great by the number indeed, but still are hopeless thugs. Andy Lau is not the least, his volubilty is as big as his courage is thin, he earns respect from his followers by dint of past accomplishements only, he hides himself under a truck and yet later describes the "heroism" he showed, he uses his son whom he doesn't even protect as a defense in court, etc...
His superiors are even more cynics, you can see them around a drink watching their henchmen beat the hell out of a snitch while the children celebrate a birthday in the garden next to them. In other words, the Underworld is truly depicted, and that hurts.
Crossed to his "professional" journey, you discover Cheung-Dee's love life, tortured as well. Wong Jing surprises us for he went further than the basic triangle love story. Because his heart dangles between his lawyer (Gigi Leung Wing-Kei) eager for newness (that he represents as a triad) and Ruby, his devoted friend (Suki Kwan Sau-Mei) with whom he shares an equivocal relation ship.
But there's a third woman, his first one, the mother of his son who died in his arms, therefore you understand the character's confusion.
Gigi Leung is touching though she never really manages to involve the audience in her different issues whereas Suki Kwan offers a quite impressive performance wich isn't really surprising from her (watch A Gambler's Story, you'll see). The fews supporting roles are well played, Prince for instance, Andy's horrid Tai Lo (Mark Cheng Ho-Nam) and also Frankie Ng Chi-Hung (Uncle Bee in Young And Dangerous), his right-hand man.
Andy Lau is excellent, he gets to convince when he acts smart & tough in front of his pals as well as when he gets humiliated by his bosses. The scene where he impress the most is when he bumps into his son, disfigured by Prince ; and leaves right away, determined to settle things with him but when he actually stumble on Prince, he only manages to light him a fag and follow him, head-hanging. Speaking generally, he shows a mind-blowing realism in every scene with his son. Cheung-Dee, for its construction and its deepness, is doubtlessly one of the best role Andy Lau never had and obviously, this explains such a quality of playing. Andy even offers an end song, revered in Hong-Kong, a bit stardust although carried by an outstanding Kenny G (american saxophonist).
In Brief, through its brutal and realistic treatment, through a top-notch Andy Lau and a Wong Jing who knows his job when he wants to, A True Mob Story is a true must-see, unavoidable in a central kind of movies in Hong-Kong cinema : triads films. A movie as good as punchy and without any "criminal seduction", because this film, as you understood, is just a true mob story.
