"I NEVER UNDERSTOOD opera until I started working with it," says Washington National Opera fight choreographer Brad Waller. "There are so many elements working together."

All of those elements converge at the Kennedy Center Opera House during a recent rehearsal for the company's "Billy Budd." Waller watches from the house, taking note of glitches and occasionally venturing onto the stage to demonstrate whip technique or oversee a difficult hold. The Benjamin Britten opera, based on Herman Melville's allegorical novella, is set in 1797 on the deck of a British man-of-war. Though the production does not contain any formal combat, it does include cracking whips, lunging daggers, flying fists and an onstage hanging.

Says Waller, 49, "I'm in charge of anything where someone can get hurt."

In "Billy Budd," where much of the shipboard action is meant to illustrate the brutality of the British navy, that's plenty. "There's a lot of harsh treatment to orchestrate," Waller says, "a lot of complicated movement that you have to make look easy." Attesting to the show's physicality, many cast members wear kneepads during the rehearsal. Each fight sequence is parsed out move by move on Waller's laptop computer, but his worries also include production elements, such as the narrow stairs that the performers descend to leave the stage and the ship's mast, which they must learn to climb safely. "There are a lot of little things," Waller says. "Sometimes they're the most dangerous."

In an unintentional tribute to the excellence of the venue's acoustics, a cast member's sotto voce "Oh boy!" when asked to climb higher is clearly audible in the house.

Waller's challenge is accentuated by the opera's stunning set -- the deck of its H.M.S. Indomitable is a steep rake that extends over the pit. In other words, the cast must not only move gracefully, but do so on a high, steep surface. The great irony of this rehearsal is that it makes the singing seem like the easy part. Baritone Dwayne Croft, who plays the opera's title character, stands on the stage eyeing the drop into the orchestra pit. "This is what I'm most afraid of in this opera," he says. Waller points out that the Washington National Opera has the best reputation for safety in the country. He himself has never been injured on the job. "I fight all day and nothing happens," he says, "then I go home and stub my toe."

Waller's long association with the company began during its fall 1991 season, when he was the fencing master for its production of "Don Giovanni." He began his study of weaponry years before while working as an actor, often in Shakespearean roles that demanded swordplay. Later, between acting jobs, he decided to teach what he had learned. "I did what I knew how to do, then got labeled as a fight guy," he says.

Though he still acts occasionally, Waller divides most of his time between fight choreography and instruction. His dictionary-thick resume records stints with nearly every theater company and university in the area. But he particularly enjoys leading stage combat workshops for kids. "I teach them that it's all about the illusion of violence," he says. "You don't create a fight for entertainment value, you create it because it's part of the story." Waller's nonviolent take on violence is more than a personal philosophy. He's quick to cite the wisdom of the 16th-century European fighting masters, who held that if you reached for your sword, you'd already lost the fight. "Most fighters are very gentle people," he observes. "I like to garden and play with my kids. Rarely do I go home to fight."

Waller may have a way with a broadsword, but he's a historian at heart. As fight choreographer, it is Waller's responsibility to make the show's violence as authentic as possible. "Every production starts with research," he says. "I try to give the director options, even if he doesn't use them." Waller moved to the Washington area in part, he says, because he'd have access to the Folger Shakespeare Library and the Library of Congress. In 1995, he was guest curator of "The Sword and the Pen," an exhibit at the Folger exploring the relationship between combat and drama. Waller hopes to eventually raise the money to mount an expanded version of the show at the Globe Theater in London.

In the meantime, he continues to fight the good fight -- or appear to. "It's mostly acting," Waller says of stage combat. "Creating an illusion that's both safe and dramatically valid." Whether the movement in question is brawl, slap, shove or tussle, one maxim applies: The victim is always in control. In that sense, stage violence is the opposite of the real thing. There are also the performers to consider. "Someone could have a bad back or a bad knee or be afraid of weapons, and you have to make them look good," he says.

Truth be told, Waller says, most stage combat is not historically accurate. If it were, fights would be "very boring and very short." Dramatic considerations always come first. In opera, that can mean eschewing realism to avoid distracting the audience from the music. "It'll often be a little more stylized," Waller acknowledges. "The audience is pretty clever," he says. "They'll either buy it or they won't."

Fight choreographer Brad Waller keeps his eyes on the stage during rehearsal for Washington National Opera's "Billy Budd."