A SON who chased down and stabbed a younger man in the back for allegedly assaulting his elderly father was jailed for two years yesterday. Jim Chan-ming, 39, was found guilty of intentionally wounding Yip Mung-yu, 26, on December 29 last year. He denied the charge. Jim thought Mr Yip had earlier attacked his 76-year-old father, Chim Kwan, at a playground in Ho Man Tin. Mr Yip, who sustained a small wound to his back, had to stay in Queen Elizabeth Hospital for 10 days. On December 29, Mr Yip was watching a group of people playing chess at the playground. He told the court that Mr Chim had shouted in his ear; in response he tapped the elderly man on the head. About an hour later, Mr Chim returned with Jim pointing out Mr Yip as the man who had assaulted him to his son. Jim pulled out a knife from his back pocket and chased the victim, stabbing him in the back. He was arrested on January 10. Deputy Judge Andree-Wiltens said the encounter was a trivial matter at the beginning but the consequences were great. He said Jim's motive was to look after his father but the court could not allow him to take the law into his own hands. The District Court judge said Jim had a criminal record, and had shown no remorse over his conduct. However, after taking into account the fact that Jim had to look after his father and that his initial motive was to help the elderly man, Deputy Judge Andree-Wiltens reduced the sentence by a year.