DOWN ON H Street, not far from Chinatown, they were doing a lot of "gambaying" over Chinese fire water -- toasting is what most people call it -- at a $75 a person banquet Sunday night. The most prolific toaster, was Undersecretary of Defense Robert Komer, who said he learned how when he went to the People's Republic of China in January with Defense Secretary Harold Brown. "The secret is to eat a lot."

Chinese fire water is called Mou Tai and it's 106 proof. There was a bottle of it on each of the eight tables at the Kowloon restaurant, where six chefs from one of Canton's most famous restaurants had prepared an 18-course dinner for about 70 people, only a few of them paying customers.

It was the inaugural banquet in a series that will take place at the Kowloon and in five other cities between now and October. They have been put together by a Chinese-American corporation, The Chinese-Culinary Institute, which is located in New York, in cooperation with the government of the People's Republic.The object is to introduce Americans to "real" Cantonese cooking, which according to the chefs who arrived in New York two weeks ago, we don't get a chance to eat.

"Chinese food in America is very Americanized," said Lo Kwan, the head chef of Canton's Pan Hsi restaurant, through an interpreter."There is a lot of sauce. There are no puddles in the bottom of our food. Here the food is not beautiful. The visual is not emphasized." Though roughly 80 percent of the Chinese restaurants in the United States serve Cantonese food, much of it is bathed in translucent, non-descript, cornstarch-thickened white sauce or doused with soy sauce.

Lo Kwan and his fellow chefs, two of whom are women, had sampled food in New York's Chinatown. Being a diplomat he said the food at the Kowloon was better than in New York. "You see the color, the individual foods."

He also said he like Washington better than New York. "New York stinks," was how the interpreter put it. "There's so much garbage. If they were in Canton they would have been fined 100 times. Washington is better. It's greener and cleaner."

The Cantonese chefs had come to the Kowloon because "it is a typical Cantonese restaurant. Presumably the restaurant's chefs were to pick up a lot of tips watching the visitors work. There is great emphasis on bright colors. Garnishes for many of the dishes had been dipped in artificial food coloring. There were birds and animals and flowers made of green and pink and yellow dough. Fried noodle bouquets contained both white noodles and noodles which had been colored green. But the most spectacular use of colors was in the cold plates which opened the dinner.

For the Chinese ambassador and his party a spectacular peacock, with tail open, had been constructed of artfully cut duck, shrimp, eggs, filled and rolled chicken slices, tea eggs, carrots cut to look like tail feathers and cucumbers sliced to look like leaves. For the other tables there were baskets, butterflies and fish. Everything was edible. The Cantonese restaurant, which has 100 chefs and serves 6,000 people on an ordinary day, many of them foreigners, is known for its cold plates and for its dim sum, little savory pastries served for breakfast and lunch or as a prelude to a banquet.

Sunday night there were dim sum no more than an inch high shaped like rabbits, complete with little black eyes; pear-shaped dumplings, smaller than your thumb, of mashed potatoes stuffed with mushrooms and pork, covered with crumbs and deep fried so that they were the color of a pear. The stems were made of slivers of ham. Crispy begonia checken were deep fried pastries with many layers of leaves, both golden and rose colored, shaped to resemble a begonia.

The cold plate and dim sum were followed by hot dishes punctuated by a soup course and finally four desserts.

Frogs legs came boneless, each stuffed with a sliver of ham and of baby corn. The chefs' attention to detail is meticulous and some of these beautiful looking dishes tasted wonderful. Whole lacquered suckling pigs were cooked to a burnished golden brown, the skin so crisp and free of fat you felt no guilt eating several pieces. The mushroom soup was made with whole black mushrooms that had been brought over by the chefs, the only ingredient they felt they couldn't find in the United States.

You know how difficult it is to get used to a kitchen that isn't your own. Think how much harder it is to get used to strange ingredients. The chefs had cooked only once in New York before coming to Washington. Under the circumstances their banquet was a tour de force.

Many of the dishes were familiar to Americans; many were not. Some were also unfamiliar to Yu Enguang, a correspondent with the official Chinese news service, Xinhua News Agency. Yu comes from northeastern China where the preferred food is Peking-style, not Cantonese. He kept up a running commentary during the meal explaining to his dinner companion what he had and had not eaten before. He pronounced the meal "fantastic."

Yu and his wife often eat at the Kowloon and at several other Chinese restaurants in town when they are not dining at home. Home is the house on S Street bought by the People's Republic of China shortly after their Mission was opened in Washington. It was designated as a house for the country's ambassador but no ambassador has ever lived there. So the government made an arrangement with other Chinese who are working in Washington and 10 of them are living there with their own chef from the North of China. Yu said he also likes the Peking on 15th Street and the Yenching Palace.

The dinner was scheduled to begin at 7, but the first dish was not served until 7:40. That's as long as the organizers felt they could safely wait for Mayor and Mrs. Barry before the paying guests fomented a revolution. The Barrys arrived at 8:10, complete with a picture of their first born taken at two days. They gamely used their chopsticks -- not everyone did -- and ate their way through all the courses they hadn't missed.

"It's good, but I ate too much," said the Mayor. "I must have gained three pounds." Asked what he would do to lose it he was ready with an answer: t"The citizens will run it off me."

Effie Barry didn't think drinking large quantities of Mou Tai in 100 degree heat was such a good idea, but Undersecretary Komer and Ambassador Chai Zemin obviously didn't agree. Chai went over to Komer's table and told him that old friends must gambay with Mou Tai three times.Komer, who said he had already had several ponies of the equivalent of top quality moonshine, was not to be outdone. But when he suggested a fourth toast to the Ambassador, Chai switched to water.

Later Komer paid a visit to the Ambassador's table and proposed a toast with what purported to be a teacup full of Mou Tai. Called on it, Komer tried to bluff his way out of having any one sample the contents of the tea cup.

"This is quite unfair," he blustered. "Mr. Minister, I'm quite disappointed in your staff. I've never run into such suspicion." And they all laughed as he downed his water and then tipped it upside down over his balding pate, as he had all the previous glasses, to prove that it was empty. This last gesture is not a Chinese custom. It's a Komer custom.

By this time the 12th course had arrived, an excellent steak kew, but no one rushed to put the chopsticks in the platter as it arrived at the table. Eighteen courses, even if many are only two bites worth, is a lot of food.

The same banquet is being served at dinner tonight, Friday and Saturday. A $25 dim sum lunch cooked by the chefs from China is also available.

After Washington the chefs go back to New York to cook, then to Smithtown, L.I., back to Manhattan and on to Philadelphia, Los Angeles and San Francisco.

The Chinese Culinary Institute plans to bring chefs from other regions to the United States and hopes some day to open a cooking school with Mainland chefs where Americans can learn "real" Chinese cooking.