Sam Shankland first met Christopher Yoo as an 8-year-old and said it was “a tremendous delight to watch him grow up”, but in Round 9 of the US Championship he beat his sometime student in the only decisive game of the Open section. In the Women’s event Jennifer Yu regained the sole lead, while Alice Lee and Irina Krush share 2nd place after playing out an amazing draw.

After Round 9 of the US Championship there are only four rounds to go, with the tension growing among those in contention for first place. That led to some incredibly hard-fought draws.

Leinier Dominguez was unable to topple Sam Sevian in 113 moves, while Ray Robson was gunning to make it four wins in a row by beating Alex Lenderman, but despite getting a clear advantage he had to settle for a draw — with the game ending on move 89 with bare kings.

Ray Robson couldn't quite catch Caruana | photo: Lennart Ootes, US Chess Champs

Fabiano Caruana’s hopes of extending his lead were thwarted by Awonder Liang, who resurrected an opening that was largely considered a rookie mistake until recently. He played the Petroff 1.e4 e5 2.Nf3 Nf6, and after 3.Nxe5 copied his opponent with 3…Nxe4!?

Chess art | photo: Lennart Ootes, St. Louis Chess Club

Chess engines are proving that all kinds of offbeat openings are still playable, however, and Kamil Plichta has produced a course on the “Damiano Petroff” for Chessable. He was on hand to comment as the action unfolded.

Awonder seemed to equalise, but lacked some precision in the early middlegame and found himself defending an endgame a very clear pawn down.

In what followed it seems Fabi missed some great chances to win his 5th game of this year’s US Championship, before Awonder managed to hold on until stalemate on move 76.

Awonder Liang has been having a lot of fun at this year's US Championship | photo: Austin Fuller, St. Louis Chess Club

There were faster draws with less drama in Swiercz-Moradiabadi and Xiong-Aronian, while Niemann-So essentially had just one curious moment. Hans has just played 19.Nh4?!

Wesley quickly responded 19…d5! and Hans even more quickly brought his knight back with 20.Nf3. He confessed afterwards:

He was proud of retreating the knight, however, commenting, “you just sort of have to swallow your pride and admit your mistake”. He regretted over-pushing in previous games with the white pieces.

Wesley So had implied earlier in the tournament that he wasn't looking forward to this game | photo: Lennart Ootes, St. Louis Chess Club

Wesley So, whose thoughts are probably already turning to defending his title in the World Fischer Random Championship in 10 days' time, had no objection to making a quick draw, and the game soon fizzled out.

Christopher Yoo has come a long way in 7 years | photo: Lennart Ootes, St. Louis Chess Club

That leaves the one decisive game, where Christopher Yoo played somewhat loosely with the black pieces against Sam Shankland.

13…f4!?, allowing White to take a pawn with check, surprised Sam:

It might have been much tougher if after 14.Bxh7+ Kh8 15.Bd2 Christopher had found the best continuation.

15…Qe8+!, planning to put the queen on h5 and apply pressure to the bishop on h7, was much stronger than 15…Qe7+?! 16.Kf1 Bg4 17.Re1 Qf6 in the game, when the queen proved to be badly misplaced. 

The big question was how White would finish off the game, and Sam ultimately found the powerful retreating moves 31.Bc2! and 32.Qf1, which left Black defenceless against 33.Rg6!

The queen has nowhere to go, with 33…Qh7 running into 34.Rxf6!, while 33…Rxg6 34.hxg6 leaves the queen pinned down the h-file. Christopher went for 33…bxc4, but only stumbled on for five more moves before resigning.

Afterwards Sam revealed that he’d known Christopher Yoo from the time the prodigy was 8 years old.

Beat them while they’re young, as they say, and that wins puts Sam on a plus score and in with an outside chance of winning his 2nd US Championship, since he still has the white pieces against the leader, Fabiano Caruana.

Ray Robson, however, is by far the best placed to challenge, particularly as he’s already played all the 2700+ players in the event.

The lead in the Women’s section continues to be something of a poisoned chalice. Megan Lee lasted one day as the sole leader as she was beaten by Gulrukhbegim Tokhirjonova, whose rollercoaster event continues.

Jennifer Yu is back on track to win her 2nd US title | photo: Lennart Ootes, St. Louis Chess Club

That enabled Jennifer Yu to regain the sole lead by defeating Ashritha Eswaran, who collapsed in a difficult position.

The most entertaining game of the day was between now 13-year-old Alice Lee and 8-time Women’s US Champion Irina Krush. At first Irina was on top with the black pieces, but suddenly Alice found a way not only to stop checkmate (the threat was Qxf2+ and e.g. Qg2#) but to take over: 37.Nf4!

37…gxf4?? 38.Qh4+ and it’s mate-in-4, so the knight is untouchable, while it perfectly restricts Black’s queen, protecting f2 and the vital h5 and h3-squares.

After 37…Bd7 38.Rd8! Rc1+, however, it turns out the most natural move in the world, 39.Kg2, let the win slip away. 39.Kh2! was the move, with the difference that in some lines Qf3 will no longer be a check, and with one extra tempo it’s White who can give checkmate.

Alice Lee had Irina Krush on the ropes | photo: Lennart Ootes, St. Louis Chess Club

The game was far from over, however, as rather than force a draw Alice went for an endgame with four pawns against Irina’s rook.

It was quite a position, but in fact simply a draw, as the players proved by playing on to bare kings on move 68. That leaves at least six players still in contention for the US Women’s title.

It’s notable Jennifer Yu still has to play three of those players, Begim, Irina and Thalia.

Round 10 of the Open section features a game that before the tournament we would have assumed would be among 1st place contenders, Aronian-So. When it comes to the title race, however, all eyes will be on Sevian-Robson and Yoo-Caruana, with Fabiano no doubt hoping to inflict a 3rd loss in a row on his young opponent.

Follow all the games from 1:30pm in St. Louis (20:30 CEST, 00:00 IST)!