If you scrunch your eyes up just as an offensive line sets for a play, the outlines of the players look like chess pieces being moved around the board by some invisible hand. Some run in the straight lines followed by a rook, some follow the diagonals of a bishop, and others hold off opponents like a pawn.

It is an old, well-worn cliché in American football that the sport is simply chess played on a field, with its complex strategies used to unlock an opponent’s defense or stifle its offense. While such a cliché inevitably oversimplifies the connection between the sports, there are parallels.

“Before a play starts, the pieces are set, this is the position on the chess board,” says Tennessee Titans cornerback Chidobe Awuzie. “When the play happens, it’s now the execution part of it. It’s chess to an extent but then once the play happens, it becomes football.”

Awuzie is part of a growing cohort of NFL players who are taking up chess as a way to unwind, improve their strategic thinking and provide an outlet for their fierce competitiveness off the field.

Even on the day of the Super Bowl in 2022, Cincinnati Bengals quarterback Joe Burrow was playing chess beforehand. There are so many players hooked, in fact, that Chess.com runs a tournament for current and former NFL players – the subject of a recent documentary by NFL films.

Now in its fourth year, BlitzChamps features NFL players each seeking to win bragging rights and a prize pot of $30,000, which is donated to a charity of their choice.

“As we pulled back the curtain, we realized there were a lot more NFL players playing on Chess.com that even we knew,” Danny Rensch, the chief chess officer at Chess.com, tells CNN.

The idea for a chess tournament contested by NFL players arose through Rensch’s friendship with Larry Fitzgerald, the legendary former Arizona Cardinals wide receiver and an avid chess player.

“We were sitting in (Fitzgerald’s) Tesla one night,” Rensch says, remembering the “movie scene version” of the tournament’s inception. “We were … pulling this stuff together and he was actively texting and calling people right then.”

Following a “lot of work,” which involved fellow NFL players Amari Cooper and also Awuzie, Chess.com hosted its first tournament with the league in 2022, Rensch explains. Players used to duking it out on the field sat behind screens instead, moving their pieces around the board. To escape the ultra-competitive world of professional sports, athletes often, ironically, turn to other forms of competition to pass the time.

Eight NFL players participated in last year’s BlitzChamps and Kansas City Chiefs safety Justin Reid claimed the title of the best chess player in the league, fending off 2022 champion Awuzie on his way to the title.

More play outside of the tournament. “A lot more people (in the Titans team) have an interest and are starting to play,” says Awuzie, “or they have played in the past and are trying to get back into it.”

Every year, the tournament has “only gotten more competitive” as the quality of chess continues to improve, Rensch says.

And as the quality of chess has improved, for some players so has their footballing IQ. Awuzie credits the time he spent studying different positions in chess for his improved ability to recognize formations on the field, and to anticipate changes within them faster.

“Little things like that happen in my head at a faster pace now,” he says. “When I made my leap, when I left the Cowboys to go to the Bengals, things were just happening and I was able to respond so much quicker. But at that same time … I had gotten better at chess so it was kind of simultaneous.”

Leveraging these lessons from chess has turned the board game into a successful industry, with high performance coaches like Seth Makowsky using it to coach athletes, including Philadelphia Eagles quarterback Jalen Hurts. His efforts have been profiled in the New York Times, the Athletic and the LA Times.

For Rensch, the biggest mistake that people make in chess – that “they get married to their ideas … versus being able to react” – is applicable to the NFL, too.

“There’s a real analogy there in … what is asked of not just the quarterback … but the safety or whoever to really react and read as to what’s being executed in any given play,” he says.

Such comparisons also stretch to basketball. Luka Dončić is a well-known chess aficionado, Victor Wembanyama played against several fans on a rainy December afternoon in Washington Square Park, New York, and Derrick Rose says he plays chess every day, even during a Drake concert.

“There’s clearly something about the fact that chess is simultaneously an unsolvable puzzle, yet in every position, there’s a best move, whether you find it or not,” Rensch says of the obsession that chess seems to prompt in professional athletes.

“And there’s something about the dichotomy of that relationship that is very, very, very difficult and challenging … You know that there’s a best move and can you find it? And yet, you also know to play chess at a high level is … almost impossible.”

For more CNN news and newsletters create an account at CNN.com