SEOUL, South Korea - A court sentenced South Korean tycoon Kim Seung-youn to 18 months in prison Monday over a sensational beating attack earlier this year against bar workers involved in a scuffle with his son.

Prosecutors last month sought a two-year prison term for the Hanwha Group chairman in the attack on off-duty karoke bar workers who engaged in the altercation with his 22-year-old son, a student at Yale University.

In its written ruling, the Seoul District Court said that Kim's bodyguards forcibly took the victims to a construction site near the capital, where the tycoon kicked and punched them. Kim also hit one of the workers with a steel pipe and threatened the victims with an electronic shock device, the ruling said.

The court said that judging by testimonies, medical records and photos, they were "seriously attacked" and three of them suffered "not a few injuries." The court did not describe the extent of the injuries.

Judge Kim Chul-hwan said Kim's responsibility for the crime was "heavy" as the Hanwha chief mobilized his social clout and corporate organization to personally retaliate against the workers.

"The violation of the law is big and is serious," said Kim, the judge, adding the attacks were carried out in a "systematic manner."

Kim planned to appeal the ruling, said Hanwha spokesman Ju Cheol-beom. Prosecutors can also appeal, though there was no word on their plans.

In his first trial session last month, the tycoon admitted to punching the bar workers during the attack in March, but denied using the pipe and stun device. The judge, however, found that the tycoon wielded both weapons during the assault.

The 55-year-old tycoon, one of South Korea's richest people, also said at the first session that he was the one who "mainly beat" the victims, and that his bodyguards took over when he "got tired."

Kim has been in jail since his May 11 arrest.

The dramatic details of the case, which media have likened to something out of a gangster movie, have drawn intense public interest in South Korea, where the heads of family controlled conglomerates wield great economic, political and social clout.

Hanwha was established in 1952 as the Korea Explosives Corp. It later developed interests in petrochemicals, finance, insurance, construction and retail. It also owns the Hanwha Eagles professional baseball team.

Kim is worth about 988.6 billion won (US$1.07 billion), according to Chaebul.com, a Web site that tracks the fortunes of conglomerate chiefs and their families.

Shares in Hanwha Corp., the conglomerate's flagship company, rose 1.3 percent to close at 54,500 won ($59), for the third straight daily gain.

Appeal courts have sometimes granted more lenient sentences than the lower court rulings in cases involving business tycoons.

In 2005, Chey Tae-won, CEO and chairman of South Korea's leading oil refiner, SK Corp., had the three-year prison term he received for accounting irregularities suspended by the Seoul High Court.