Steven Cardenas ate four slices of pizza, two more than usual, while Michael Peguero simply took his trophy and went home.

Some jumping up and down might have been more fitting: The boys and two classmates at I.S. 318 in Williamsburg had just beaten Edward R. Murrow High School, a team dubbed the Kings of New York, stealing a crown held for longer than Murrow’s coach could remember — Brooklyn high school chess champions. The average age of the new champs is less than 13.

“It’s like a minor league team beating the Mets,” the sports reporter who gave Murrow’s team its name, Michael Weinreb, said. The school has won seven national championships, the most recent in April.

Steven Cardenas, 11, had never heard of Mr. Weinreb’s book chronicling Murrow’s chess program, “The Kings of New York.”

“I don’t know how they could be the kings of New York, if we’re better than them,” he said.

Before the match on Thursday, the high-schoolers took some shots at Steven, who is short even for his age, saying, “You’re so small” and “You don’t know how to play chess.”

“One of them was laughing at me,” he said. “But then I beat him.”

His coach, John Galvin, an assistant principal at I.S. 318, inserted the pre-teenagers into the high school level as a challenge. “Just to try to beat Murrow,” Mr. Galvin, who wears a windbreaker over his suit and whose office is littered with chess trophies, said. To his delight, I.S. 318 won, scoring 14 points to Murrow’s 12 and a half.

Like Murrow’s, I.S. 318’s chess program has risen despite demographics. The student body’s poverty rate is more than 70% and a security guard keeps constant watch at the front door. Saturday tournaments proceed on worn-down Formica cafeteria tables. Yet I.S. 318 regularly defeats teams from the nation’s top private schools, as well as local rivals. Columbia Preparatory, Hunter, Horace Mann — “they’re toast,” an English teacher, Peter Kelly, boasted.

To Steven Cardenas, the Brooklyn victory was just a blip next to the cinematic drama he’d lived four days earlier at the national championships, one that climaxed in a minutes-left, game-determining face off.

His team had arrived at nationals 30 minutes late, sprinting out of a rented Hertz minivan and straight to their first matches before Mr. Galvin had a chance to park. They’d already missed a connecting flight on the way from New York, and then — at 10 a.m., three hours before the tournament began and 230 miles from Nashville — realized their last flight was cancelled too. “Luckily,” Mr. Galvin said, “the speed limit in Tennessee is 70.”

Most of the teammates won their first-round games despite the 30-minute handicap. Steven won the last battle, too, handing the school its fourth national championship.

High-level competition has become the norm at I.S. 318. The chess teacher, Elizabeth Vicary, posts each player’s rating and rank on a sheet outside her door. Every year, players get team T-shirts; on the back, Ms. Vicary prints a name and a number, the player’s rank.

The boys do their homework during lunch to free the rest of their time for chess — games after school; solitary sessions memorizing strategies with names such as “The Dragon,” ” Vienna,” and “Caro-Kann.”

Some at I.S. 318 make fun of the chess team. “They’re probably just jealous,” one of the national champions, Daniel Maciag, said. He can no longer fit all his trophies on his 6-foot-long shelf.

The quick accumulation of accolades is the reason their teachers think the game is so powerful. In no other subject, Mr. Galvin points out, can hard work pay off so quickly, and so publicly.

Even the Murrow coach who built the Kings of New York, Eliot Weiss, is impressed. After pointing out that his four strongest players did not attend the Brooklyn competition (“It’d be sort of like Michael Jordan playing with a bunch of 3-year-olds,” he said), he congratulated the new kings, calling them “a dynasty.”