Nicole Bengiveno/The New York Times One of the thousands of public chess boards in city parks.

Updated, 6:10 p.m. | Wherever you find yourself in the city, there is probably an outdoor chess table nearby. According to the parks department, there are more than 2,000 public chess or checkers tables spread among 536 parks, offering the perfect spot to sacrifice a queen or promote a pawn.

Unless, apparently, the chess tables are inside a playground.

Seven chess players in Upper Manhattan found this out the hard way, when police officers approached them at the stone chess tables in Inwood Hill Park and issued them summonses for failure to comply with signs.

The tables are behind the gates of the park’s Emerson Playground, which the signs in question state is off limits to adults unaccompanied by minors.

Similar signs are posted at most if not all parks department playgrounds to deter what a parks official called “inappropriate adult use of space designated specifically for children.”

But given that the overwhelming majority of users of public chess boards are adults and what seems to be the generally nonthreatening nature of the chess players, members of the Inwood Hill Seven wondered about the logic behind the crackdown, which took place Oct 20 and was reported by the online Manhattan news site DNAInfo on Wednesday.

“What is so harmful with chess?” asked Yacahudah Harrison, 49, a homeless man who said he and four other men were playing at the tables around lunchtime when three police cruisers drove into the park. “It’s a quiet game but it still disturbs the peace.”

Mr. Harrison, a white-bearded man with a personality reminiscent of Santa Claus, said he began playing chess in the park two years ago after a neighborhood resident who saw him playing in the 207th Street subway station invited him to come to the park to teach the game to children.

“From what I know, chess is accepted as good culture in every culture,” he said. “We drink jasmine tea and have some muffins, nothing decadent.” The police, he said, “rolled up on us like we were big-time drug dealers.” The tables are separated from the rest of the play area by a fence.

Mr. Harrison and his codefendants are charged with violating a provision of parks regulation 1-03 formally known as “Failure to Comply with Directions of Police Officers, Urban Park Rangers, Parks Enforcement Patrol Officers, or Other Department Employees, or Park Signs.” It carries a $50 fine. They must go to court on the matter on or before Dec. 28.

While the park does have its share of drug dealing and other illicit activity, supporters of the chess players say that the police are going after the wrong people.

“This incident is an embarrassment to the officers from the 34th Precinct who felt that it was necessary to use their badge and authority to issue such a random summons,” Joanna Johnston, who said that her 7-year-old son learned to play chess from the men in the playground, wrote in a letter to the police and the mayor.

But the 34th Precinct’s commanding officer, Capt. Jose Navarro, told DNAInfo he had reviewed the summonses and stood by them. And a police spokesman said that the summonses were part of a larger campaign to clean up the park, driven by complaints from residents about crime.

“There’s been an effort over time to address these concerns, and a lot of it begins with very simple innocuous violations such as this,” the spokesman said.

Mr. Harrison said that none of the chess players had returned to the playground since the incident.

“We’re not looking for trouble,” he said. “We’re not lawbreakers.”

Dylan Loeb McClain contributed reporting.