One of the biggest comebacks in chess is happening right now in St. Louis

The US Chess Championship and US Women’s Chess Championship are underway in St. Louis.

On the women’s side, 2015 champion Irina Krush is shooting for history and her 8th title, putting her just one behind Gisela Kahn Gresser, a mid-20th-century player who dominated the game in her era. Krush is currently trailing the leaders by half a point.

On the men’s side, the field is phenomenally strong — possibly the “strongest ever,” according to Grandmaster Maurice Ashley, who dropped by Business Insider’s offices before the tournament kicked off to discuss all things chess, including his historic induction into the US Chess Hall of Fame, the first African-American to be according the honor. (Ashley is part of a superb commentary team, among the best in all of sports, that has once again reassembled for the the US Championships; he joins US champs Yasser Seirawan and Jennifer Shahade.)

Three men from the world’s top 10 are in the field: US number one and world number three Fabiano Caruana; US number two and world number six Hikaru Nakamura; and US number three and world number 10 Wesley So. Fleshing out the rest of the men’s lineup is a welter of promising young players and veterans, including GM Gata Kamsky, a former US champion.

Both Caruana and Nakamura came to St. Louis — home to the Chess Club and Scholastic Center, the most impressive chess venue in the US — immediately after the Candidates Tournament in Moscow, where Carauana narrowly missed a chance to challenge World Champion Magnus Carlsen for his crown later this year and become the first American World Champion since Bobby Fischer in 1972.

Caruana, 23, had every right be devastated by the loss to Sergey Karjakin, a Russian GM who will face Carlsen in New York in November. But Caruana came to St. Louis in good form and with good humor — and he’s now tied for the lead with So. Both players have 6 points and haven’t yet lost a game.

Importantly, Caruana notched a win against Nakamura, who easily won the tournament last year. It was a smashing game, with Nakamura essaying the ultra-sharp Najdorf variation of the Sicilian Defense as black and for much of the game looking like he had solid chances with his bold style of play — until Caruana, one of the finest calculators of lines in the game, found a crushing move that refuted a rook sacrifice by Nakamura, leading to a resignation.

Here’s how it went down.

Nakamura is driving forward an attack on white’s kingside, but his queen is awkwardly placed on the other side of the board and Caruana has threats of his own against the weekly defended black king (there are only those two pawns, and of course Nakamura has sacrificed a defensive resource in one of his rooks).

But then Nakamura overplays his position by grabbing the pawn on the a4 square:

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Caruana finds the perfect move: rook to a3. It’s crushing because the bishop will have no escape and eventually be lost, and there’s just not enough oomph in Nakamura’s attack on the well-protected white king to prevent Caruana from unleashing his own mating sequence on the black king.

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Nakamura tries to make something happen with his attack, but it’s lights out for that bishop on a4.

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A brilliant game from Caruana, but it all hinged on a single move — and that’s why we love the Sicilian Defense! It leads to sharp positions that have to be deeply pondered, especially for black, lest matters come undone in a hurry.

To be completely fair, Nakamura has been no slouch himself in the tournament. He’s only half a point behind Caruana and So — and he, too, is bouncing back from the Candidates and his own failed effort to take on Carlsen.

A more elaborate analysis of the game is available on ChessBase.