A SON took revenge on a man who had assaulted his 77-year-old father by stabbing him in the back, the District Court heard yesterday. Jim Chan-ming, 40, unemployed, stabbed 26-year-old Yip Mung-yu with a small knife as he was watching a chess game inside the Valley Road Estate playground in Ho Man Tin on December 29 last year. Deputy Judge Andree-Wiltens convicted Jim who had denied the wounding charge. Connie Fung, defending, said the man was concerned for the welfare of his father, Chim Kwan, who told Jim he had been assaulted by Mr Yip earlier that day. The court heard Mr Yip and Jim's father were watching a chess game in the playground of the estate and Mr Yip, annoyed by the elderly man's loud voice, tapped him on the head. The man was then told to leave and later told his son. Jim then went to the playground to look for Mr Yip. Prosecutor Philip Tang told the court Jim, who was wielding a knife, chased Mr Yip who had tried to run away. The attacker then stabbed his victim in the back after Mr Yip tripped and fell to the ground. The court heard Mr Yip was in hospital for 10 days after the assault, which was witnessed by a 15-year-old youth playing basketball nearby. In mitigation, Ms Fung said the father was Jim's only living relative and the two were very close. Jim lost his job as a decoration worker last December after he was wounded by a robber. Since then the two depended on public assistance. Ms Fung said Jim was also responsible for caring for his father who was frail. He had nothing to gain from the incident. He was simply over-concerned about his father's welfare. The judge adjourned sentencing to August 25 for background reports.