A 37-year-old Korean microsystems engineer was shot and killed Monday night during a robbery at the Central Avenue Market in Southeast, D.C. police reported.

Chang Yol Yu of 4113 Weller Rd., Wheaton, was shot once in the chest with a shotgun after two men entered the market at 5575 Central Ave. SE about 8 p.m. and demanded money. Chang was pronounced dead on the scene by the D.C. medical examiner.

Chang, who was employed by a private firm in Beltsville, had stopped by the store to help his wife, Duck Ja Yu, who had purchased the market in October. The distraught widow told a reporter yesterday that "I don't know how to tell my situation."

Meanwhile, friends of the family called attacks on Korean-owned businesses their "greatest concern." Chang's slaying was the third in holdups of Korean-owned businesses in less than a year in Washington.

"We know the economy is down and the job situation is rough," said Han Yong Cho, president of the Korean Association of Washington. "But we are just new immigrants, trying like everybody else to do the best we can to set up a new life, to get from under being an employe to owning something ourselves."

D.C police Lt. William Ritchie said, "I don't see any targeting" of Korean businessmen over other victims of similar crimes. "The phenomenon of a person complying and being shot is not peculiar to the Oriental because in the majority of cases we have closed and we have talked to the defendant in the case and we ask them why did you kill the man after he turned over the money, and he usually says because of panic or accident," Ritchie said.

But some members of the Korean community say language barriers and differences in customs make them particularly vunerable to robbers. Many store owners take English classes, they say, while others go to churches in black neighborhoods in an effort to better understand the people who live in the areas where they work.

"We are trying to improve our relations," said Seung Ahn, president of the Korean Chamber of Commerce here. "We want to know: What is the best way to avoid the problem when the gunmen comes in? The police showed us a movie, and we got a lecture. Last year, we collected money and bought hams and distributed them throughout the neighborhoods. We will do it again."

According to Seung, there are about 1,500 Korean businessmen in the Washington area. Police estimate that they own about half of the mom-and-pop grocery stores in town.

Chang, who had two children, aged 11 and 8, came to Washington from Seoul in 1974. His friends said he was aware of the dangers of owning a small business, but decided along with his wife that being an owner rather than an employe was worth the risk.

Chang died instantly of a shotgun wound to the lower middle of the chest. Police were seeking the assailants last night.