September is a time of rebirth for chess. With schools back in session, students are returning to their chess clubs. And in Mexico City, eight of the world’s top grandmasters have been competing in a championship tournament.

Some of those students may be dreaming of vying for the title, now held by a Russian named Vladimir Kramnik.

More likely is that they will someday vie for a few dollars in Union Square Park in Lower Manhattan against the likes of a man known as Russian Paul.

One recent night, Paul was studying the board before him, not far from the subway entrance. With close-cropped gray hair, arms covered with tattoos, heavy bags under his eyes and a faded and slightly tattered green T-shirt covering his paunch, he seemed out of place playing a game with such an intellectual pedigree.

But after a few seconds, Paul made a move and touched his side of the chess clock. His opponent quickly replied, and soon their hands were flying across the board, knocking over pieces and slapping the clock’s buttons.

Finally, Paul gestured at his opponent’s side of the clock, which was flashing a set of dashes, meaning his time had expired. He had lost. Paul’s side of the clock showed only seconds remaining. The players reset the board and the clock, and repeated the scene over and over, with Paul usually winning, well into the night.

Paul is one of a small legion of chess players in places like Union Square Park, Washington Square Park and St. Nicholas Avenue and 141st Street who make a living, or at least some pocket money, from hustling. Like basketball, chess hustling is a city game — fast and gritty and played on street corners and in parks with the throb of street life as a backdrop.

At the top levels it is polished, with high stakes. While the World Chess Championship, which began on Thursday, has $1.3 million in prize money, on the street the bets are usually $5 a game, and the quality of the opposition is unknown.

Another hustler, whose first name is Kenny and whose street name is Little Daddy (he is 5 feet 3 inches tall), said he could always tell how good his opponent was in the first couple of moves. For example, he said, if someone moves quickly but fumbles the pieces, or uses one hand to move the pieces and the other to hit the clock, which is against the normal rules of speed chess, then the person is not experienced.

Little Daddy, who said he started playing street chess in 1976, said he won about 80 percent of the time. A crucial part of the game is not to win too quickly, he said.

“You make the games close,” he said. “You don’t want to crush them. You want to leave their ego intact, because you want to keep them coming back.”

Russian Paul, who displayed the opening knowledge, speed and tactical ability of a master (but not the much higher grandmaster), said he had been playing in the streets for about 15 years and always tried to win. “If they get scared away, it is not my problem,” he said.

Like bartenders, the chess hustlers have names for people who keep coming back and coughing up money: regulars, or customers.

Little Daddy said that every hustler — there are about a dozen in Union Square, although the number fluctuates during the day — had at least a couple of regulars.

On this particular night, Carl Neblett, a regular, was taking on Junior, who always wears a baseball cap and keeps up a running commentary as he chain-smokes his way through games.

Mr. Neblett, who said he was an ambulette driver, said that playing against the hustlers helped him improve his game and that he had no illusions about his skill.

“Everybody here is adults; they know what they are getting into,” Mr. Neblett said, adding: “I like to think that I am smart. After losing $10, I pretty much shut it down. And sometimes you get lucky and you take these guys.”

Technically, playing chess for money is unlawful gambling, according to Jama Adams, a spokeswoman for the city’s parks department.

But a police officer at Union Square, who would not give his name because he was not authorized to speak for the department, said that he was not so sure, because the hustlers were not taking a cut of the stakes, which is how illegal gaming houses break the law. Even if what the hustlers are doing is illegal, he added, it would be hard to prove unless you watched them carefully and saw the money changing hands.

Hustlers said they had almost never had trouble with the police. Still, most were reluctant to give their full names, and were cagey when asked about their street earnings. Most said that on a good night, they might earn $150 to $200, but a slow night could produce as little as $30.

Russian Paul said he usually did not play for money. Instead, as he described it, he gives lessons for $45 an hour.

Paul is in his early 40s, younger than he appears, and is not actually Russian; he’s from Ukraine. And though by association his nickname would suggest a childhood spent hunched over a board, he said he picked up the game only after coming to the United States when he was 15.

He said he had a couple of jobs teaching chess in schools in the past, but he does not teach formally now. Fortunately, he said, he lives in a rent-stabilized apartment not far from the park, and he has no children, so his needs are minimal. Six years ago, he said, he and his wife “went separate ways.”

Not all the players give so much of their lives to the game. Leonard Rock (which he said was his real name; his chess name is Master Rock) said he worked in the billing department at Manhattan Total Health and sometimes played after work.

But for others, playing chess in the streets leaves room for nothing else.

“Chess is my life,” Little Daddy said. “You can’t play chess and have a girlfriend, because they don’t want you playing chess all night.”