Amid the clamor of customers waiting to buy a can of soda, potato chips and other groceries, Tong Kim stands next to the door and sighs, holding back tears as customers pat him on the shoulders.

"Sorry, man," one brawny patron says as he pushes the door open. Another just looks into Kim's eyes and shakes her head.

His customers are black, and Kim is a Korean immigrant who speaks little English. He is not able to respond in words, but his sorrow is universally understood. In the weeks since the Aug. 1 fatal stabbing of his brother, Thomas Kim, the neighborhood has grieved with Tong Kim in an unusual show of togetherness.

The assailant, suspected of holding up several other Korean-owned grocery stores, stabbed Thomas Kim as they struggled on the sidewalk outside the store at 1828 First St. NW. One person has been charged and is awaiting trial.

For the moment, Tong Kim is not viewed by the black residents as the foreign stranger who has come to milk the predominantly black neighborhood of its meager wealth. He is not the businessman who will sell his store once the price is right and leave without a thought about the neighborhood.

Kim for now is a man who lost his brother. His predicament transcends all racial lines and resentments that have plagued economically blighted neighborhoods where Korean Americans have opted to do business.

"They generally go through the same thing," said Inspector Richard Pennington, a D.C. police official in charge of community relations, noting the tensions that have troubled blacks, then Jews and now Koreans in their attempt to join the mainstream. "It's got to get better. It's not going to get worse."

In the District, nearly half, or about 2,000, of the city's small stores -- dry cleaners, liquor stores and grocery stores -- are owned by Korean Americans, according to Korean American business associations. Most of them are in neighborhoods that are predominantly black.

The Korean Americans, whose ancestral country is the size of Indiana, "have taken over the small mom-and-pop stores which were run by hardworking Jews," said Henry Shin, president of the recently formed Korean American Chamber of Commerce. "In 10 years, we'll be gone and the Vietnamese or some other group will dominate the corner stores."

In the early 1970s, when large numbers of Koreans began to arrive in the United States, automobile service stations were the most popular business ventures undertaken by Koreans in the District.

"In 1973, gas stations were almost free," said Sun Kun Chang, a certified public accountant who has served the Korean community in the Washington area for 20 years. "Big oil companies liked Korean owners because they would open all day and all night. Korean service stations would fix a car even though it was closing time."

Many gas stations were run like family businesses with the father as the manager and sons or cousins pumping gas, Chang said. The same manner of running a business carried over to grocery stores, liquor stores and dry cleaners that replaced the service station as the chief business for most Korean Americans, Chang said.

"If three people in the family make $20,000 a year each, you can make $60,000 a year, thereby saving $40,000," said Han Yong Cho, who runs a grocery wholesale business in Capital City Market on Florida Avenue NE. "I'm no better than the previous owner, but this is what you need to do to make it here if you're an immigrant."

For some recent Korean immigrants, many of whom do not speak English or understand the culture, the streets have become their way of making it in the United States. "Many Koreans are taking up vending, because the process of doing it is easier," Pennington said.

According to street vendors, licenses are easily acquired if you can prove you are a resident or a citizen, and there are few restrictions on where you can have a stand. Expect for a few spots around the District, such as the Mall area where a daily lottery is held for spots, vendors are permitted essentially anywhere.

About half of the approximately 600 vendors in the city are said to be Koreans, and they sell nearly everything from half-smokes to pantyhose without having to say much.

With four fingers raised, a vendor indicates "four dollars" to a potential buyer at 15th and K streets NW. When the sale is done, he thanks the customer and says, "Come again." For the next hour, the same words are said over and over.

"Pantyhoses and earrings sell well in the morning," said a Korean vendor, who wanted to be identified only as Mr. Bae. "If a woman who's rushing to work loses an earring or needs pantyhose right away, they can come to me and buy one or a pair real cheap."

It is estimated that the Washington area has the fifth-largest population of Korean Americans in the United States, about 40,000, according to the latest available data, based on the 1980 census. Community leaders say there may be as many as 60,000.

The community has grown to such an extent that a 388-page telephone directory is published each year by the Korean Association of Greater Washington; it lists the names and telephone numbers of Korean Americans living in the Washington area.

But only about 600 Koreans are said to live in the District, most of whom are college students. The fact that a majority of Korean American store owners commute from Maryland or Virginia has contributed to some resentment among black residents, who view them as outsiders taking jobs from blacks.

Also, being scattered in the two states has meant that the Korean American community has not been able to become a viable political force.

"By and large, they are working hard to establish an economic base," said James Kim, an adviser on Asian affairs to the mayor. "They need to do that first."

In an attempt to do that, Korean merchants have dealt exclusively with each other in business transactions -- a pattern that has further increased tensions between black residents and store owners.

"When Koreans leave this area, they sell the store to other Koreans, which further exacerbates the problem," said inspector Pennington, who has been instrumental in bringing the two communities together to alleviate tensions.

Many Korean American merchants contend that because of cultural and language barriers, it is easier for them to sell their stores to other Koreans. "There is mutual trust in the transaction you would not normally have if you were dealing with non-Koreans," Korean American chamber official Shin said.

That trust is embodied in a Korean tradition known as kehs, in which members of a group contribute a certain amount into the pot each month with the members taking turns taking the total sum home. Each member must trust that all the members will contribute each month. By doing so, Korean Americans have been able to supplement their savings and purchase stores that otherwise they could not afford.

Still, a majority of Korean American merchants have saved for a store of their own by working long hours as a janitor, a busboy or a vendor on the streets. In many cases, man and wife work side by side at such jobs.

"Doctors complain about Koreans," Chang said with a grin. "There are people who work three jobs: In the morning, they run errands; at lunch time, they wash dishes, and at dinner time, they cook. They don't have time to go see a doctor, so they only go when they can't work anymore."

"Because we're from a small country, we've learned to work hard and be frugal with money," said Shin, who came to the United States with about $20 in 1970 and now owns a dry-cleaning establishment in Southeast Washington.

Like his fellow merchants, Thomas Kim bought the store in Northwest Washington with money saved while working, in his case as a mechanic at an ice cream company. Thomas Kim even had enough money to send for Tong Kim, so he could help in the family business.

"It was such a shame," Tong Kim said, his soft voice cracking. "He wanted to live an American dream and he never got to."