At 10:30 a.m. Minoru Kiyota marches to the front of the blackboard in a classroom at Walt Whitman High School in Bethesda and utters a one-word command, "Hajimemasho" which means "let's begin" in Japanese.

"Ki o tsuke" or "attention" says one student. "Rei" or "bow" says another. The entire class bows and the lesson begins.

The bowing ritual, which is repeated every day at the beginning and end of the school day in Japan, is being practiced with a slight variation by students learning Japanese at two Montgomery County high schools this year. The difference in the ceremony is that in Japan students must rise from their chairs before they bow, but here they are allowed to remain seated.

Kiyota, a soft-spoken Japanese teacher with a polite manner, has adapted this foreign custom to the American school setting in a county with a growing number of international residents. An official with the consular office of the Japanese Embassy in Washington estimates 50,000 Japanese are living, working and studying in the metropolitan Washington area.

Kiyota is in the United States on a teacher exchange program between his home state of Kanagawa Prefecture, near Tokyo, and the state of Maryland. Although the program is five years old, Kiyota is the first Japanese teacher to be assigned outside the Baltimore schools.

As part of the exchange, Bonnie Cochran, a social studies teacher at Bethesda-Chevy Chase High School, is teaching English language and culture to high school students in Kanagawa Prefecture.

Kiyota is helping to teach advanced Japanese classes at Walt Whitman and started a beginning Japanese class at Einstein High School in Kensington.

The class at Einstein fell to Kiyota unexpectedly. Right before school was to begin in September, the teacher who was to teach the new class was promoted and there was no one to replace her.

"Kiyota learned about it and volunteered to take it," said Richard Wilson, coordinator of secondary social studies for Montgomery County Public Schools.

"He said 'the honor of a Japanese gentleman requires me to do it.' It was such a nice thing to hear."

In the classroom, Kiyota has laid down strict rules in accordance with the style of education in Japan. "No chewing gum, as often as possible sit up please, regular attendance please, homework please, and be honest please," said Kiyota, who has taught English in Japan for 17 years and said he entered the profession because "it is my life's blood."

At Walt Whitman about 90 students study Japanese in a program that was begun seven years ago by Jean Morden, a teacher who learned Japanese during World War II. The class at Einstein has about a dozen students.

A few Walt Whitman students are in their fourth year of Japanese and many say they plan to continue studying the language in college.

Some, like 18-year-old Kenneth Goldsmith, a senior at Walt Whitman, are thinking of such professions as engineering where, because of the technological exchange between the two countries, they can use Japanese.

"At first people thought I was weird for taking Japanese, now they think it's neat," said Goldsmith, who is in his fourth year of Japanese.

Others study Japanese for personal reasons.

"My parents want me to take it because they speak perfect Japanese," said Moonsu Kim, 18, whose parents are Korean. "Now my parents can't talk secret words in Japanese anymore."

Kiyota, who is always referred to by his students as Kiyota sensei, the Japanese word for teacher, said he strives to give his students a combination of Japanese language and culture.

A small-framed, bespectacled man with a pleasant smile and a quiet manner, Kiyota, 40, glides effortlessly across the classroom, pointing to students and asking them questions.

In addition to doing translations and memorizing hundreds of kanji, Chinese ideographs that are used by the Japanese in their written language, Kiyota's students also are shown slides that depict most aspects of Japanese life from temples to sushi. They are then asked to describe in Japanese what they see.

Kiyota has gone to great pains to explain how the Japanese public educational system is different from that of the United States.

He is puzzled by the fact that in America students attend school five days a week for a total of 185 days of school a year, while in Japan students attend school six days a week for a total of 245 days a year.

"I wonder what [American students] are doing when they are not in school," he said.

Kiyota also has found that Japanese students are different from their American counterparts. He said he has been pleasantly surprised by the openness and individuality of American students who ask questions often and have no fear of offering their opinion.

In Japan, he said, students are good at "memorization and cramming knowledge" but not at expressing what they are thinking.

"Education in Japan is passive," he said. Although students are allowed to ask questions at the end of a lecture, they do not readily express their opinions and are taught that it's important to compromise whenever possible. "Silence is not a bad virtue in Japan," Kiyota said.

While Kiyota, who has been in the United States since March 1984 and taught several classes in Baltimore before coming to Montgomery County this fall, is thoroughly enjoying his American teaching experience, he misses his wife and two sons, ages 8 and 10, who remain in Japan.

Wilson said he was recently in Japan and visited with Kiyota's family. He said he brought back some slides of Kiyota's hometown.

"When I showed him the slide of his wife he rushed up to the screen and kissed it. He said, 'Oh my wife, it's so nice to see her.' "

But Kiyota has made many friends here who have assuaged the pangs of homesickness.

Suzanne O'Hatnick, executive director of the International Visitors Center of Baltimore, a nonprofit organization that arranged the exchange program for the state of Maryland, said Kiyota spent Thanksgiving and Christmas with her family. "When he arrived he was very proper," she said. "Now he is more relaxed and laughs and is comfortable."

As the time for Kiyota's return to Japan approaches (he is scheduled to leave in March), he has begun thinking about what he will tell his fellow teachers about this country's educational system.

He said he plans to tell them about the amount and quality of learning materials and the nice school buildings in this country. He said he is especially impressed with the heating system in American schools. Japanese classrooms have stoves that do not heat evenly, he said. He also will tell about the benefits of smaller classes. In Japan, high school classes average about 45 students compared with less than 30 in Montgomery County.

But Kiyota's most important lesson will be for his Japanese students.

"When I come back to Japan I have to encourage students to . . . speak out more fully what they are thinking . . . without losing their modesty and politeness," he said.