"Ah-Ten-Shunt!"

At the barked command, 160 children instantly put away childish ways and stood with determination in their eyes, concentration on their faces and business on their minds.

They were members of the Shaw Junior High School marching band, preparing to take their places in Howard University's homecoming parade yesterday, and there would be no tolerating anything less than excellence. In the silence of their rigid stance, eyes ahead, the uniformed platoon of youngsters, 12 to 15 years old, showed they knew that all too well.

Several miles away, standing in the morning-damp grass of Rock Creek Park, about dozen members of H.D. Woodson High School's marching Warriors closed their eyes and huddled, pressing as close together as they could. They touched hands over drumsticks and recited the Lord's Prayer. In a half hour or so, they would be bringing up the rear of the homecoming parade of the University of the District of Columbia, marching along 16th Street through the stately neighborhoods of upper Northwest Washington.

It was a big day for the city's high school and junior high school marching bands, the day of the big Howard and UDC homecoming parades. Schools engaged in a friendly crosstown rivalry, each striving to outdo the next in music and moves.

But for the more than 1,000 youngsters who stand in the ranks of their school marching bands in Washington, being a Woodson Warrior or a Shaw Junior High Hawk or part of Dunbar High's "Wave Machine" or a member of Cardozo High's "Crowd Pleasin' Band" is more than snappy tunes and flashy coats with shiny buttons, more than fancy footwork for the crowds.

"It's giving it my all, not letting anybody down. It's holding up my end of the bargain," said Michael Jones, a 14-year-old ninth grader at Shaw. "The band has given me courage to go out before people and perform."

For Theodore West, a trombone-playing senior for Ballou High School in Southeast Washington, band is "something to do that is worthwhile. A lot of young people are looking for something to do." For Easterm High School's David M. Wright, 18, a school's marching band is the repository of a student body's pride.

Band directors say they don't have the resources they need to make the band experience available to all the students who want to have it. Ballou's band marches in hand-me-down uniforms from a school in New York; 16 members of the Dunbar High band wear a huge "R" on their backs and "Rockridge" on their shoulders because their uniforms came from a school in Illinois.

Following a break-in and burglary this summer at Woodson, Band Director Charles Hankerson said with a shrug of helplessness, "I had six students looking at one flute. What are you going to do?"

But despite the problems, yesterday was a day of musical celebration and pageantry, when marching musicmakers -- accompanied by ROTC drill teams and color-coordinated banner and pompon girls, flag twirlers and majorettes, all led by high-stepping drum majors -- took to the streets during the two homecomings. A showdown for bragging rights was inevitable.

"One-Two-Three-Four-Shaw!" shouted the 160 Maching Hawks in the Howard parade as they thrust their hips forward and bowed their backs in an exaggerated gesture before snapping to attention. In front of them, the band members could hear the infectious drum cadence of the Fletcher Johnson Education Center Marching Wildcats. But the Hawks would not move, not even dare to tap a single white marching shoe. Band Director Lloyd Hoover expected perfection, and was getting something very close to it.

The day's parade was a warmup for the Shaw's upcoming appearance in the Gimble's Thanksgiving Day Parade in Philadelphia. Last year, Shaw became the first junior high band to participate in the 62-year-old parade.

In minutes, at Hoover's command, his band began to rock. Knees were lifted, toes pointed, instruments began to sway in beat. First there were drums. Then a chant: "SHAW WILL MAKE YOUR BODY MOVE." Then music. The band moved out and there was the sound of Barry White's "Change" with its complex harmonies.

Back at Rock Creek Park, chartered Metro buses dropped a seemingly endless succession of high school bands behind the park's tennis stadium for the UDC parade. Each would line up and march to its place on the field, members eyeing the other bands, believing they possessed something special that the others lacked.

Angela Holson, 17, of Dunbar, conceded that Woodson was probably the best marching band in the city. It had the trophies, awards and invitations, including this year's to march in the Cotton Bowl Festival Parade in Dallas. The band is trying to raise $43,000 so it can make the trip.

"But we have the discipline," she said with a smile. "Discipline. That counts for something."