The long standing and evenly matched online rivalry between Magnus Carlsen and Hikaru Nakamura took another twist on Sunday when the five-time US champion and popular streamer edged out Norway’s world No 1 14.5-13.5 in the $100,000 chess.com speed championship final.

The event, a four-hour mix of 5/1 and 3/1 blitz and 1/1 bullet, is a marathon test of fast reactions, creativity, and resourcefulness under extreme and constant time pressure, and this pair have monopolised it. In 2016 and 2017, Carlsen beat Nakamura in the final; since then, with Carlsen mostly not competing, Nakamura has won five years in a row.

The result of their latest battle was arguably influenced by outside factors and by the small print of the rules. In the opening 5/1 segment (five minutes per player for the entire game, plus a one second per move increment) Nakamura scored a dominant 6.5-2.5 without loss, as Carlsen lacked energy and made uncharacteristic errors. He had spent two hours of preparation time watching and supporting France against Argentina.

Nakamura sensed his opportunity as early as game two: “For me the moment that I knew that I was going to have chances was probably the second game, when I played the King’s Indian, and Magnus did not put me away. He was up a pawn, it was a very typical Magnus type of position, with a great knight on f5, but in the time scramble he was very shaky and the game ended in a draw, and I think from that time on I felt good about my chances, because it was just very uncharacteristic for Magnus to not be precise there.”

Carlsen highlighted game three as “a bit of a meltdown” and regretted he had not been more solid as Black. In game five, Carlsen’s offbeat gambit (1 Nf3 Nf6 2 d4 b6 3 c4 Bb7 4 g3 e5?! ) turned out to have been played long ago by both Alexander Alekhine and Mikhail Botvinnik, but the experiment misfired, and in game eight he lost with White as Nakamura’s rope-a-dope with his queen on the back rank led to this week’s puzzle diagram.

Four down after the 5/1 segment, Carlsen launched a recovery, winning the 3/1 section by 6-4 and the 1/1 by 5-4. and briefly levelling the scores before Nakamura edged ahead right at the end. His comeback still had a horrific moment when, in a routine position, he played Bf4-c7 to attack a d8 rook and Nakamura replied Na6xBc7, inducing immediate resignation.

Hugh Alexander, the England No 1 of his time and a Bletchley Park codebreaker, used to say that backward diagonal queen captures were the hardest to spot, but perhaps backward knight captures should be added.

In the final game, Carlsen was two queens ahead, but Nakamura was able to delay mate until the match clock time ran out and there was no time to start another game. Carlsen would still have needed to win that to force a four-game tie-break and a potential Armageddon. The complete match can be viewed at chess24.com.

Carlsen and Nakamura now travel to Almaty, Kazakhstan, where the over-the-board World Rapid and Blitz championships have their opening ceremony on Christmas Day, followed by three days of rapid and two of blitz from 26-30 December.

Carlsen has won three Rapid and four Blitz titles, and holds the record for the highest ever blitz rating of 2948. In contrast, Nakamura has never won either title, although he is rated the No 2 in blitz, behind Alireza Firouzja but ahead of Carlsen in fourth. Both tournaments are highly competitive, many players have a realistic chance, and the new teenage generation will be eager to impress.

Rapid chess in the UK received a major boost this week when the ECF and 4NCL announced that the 2023 British Rapid Championship will be staged in Bradford on 15-16 April. It will be an 11-round Fide-rated Open, with a £3000 prize fund.

This is an enhanced version of what used to be an annual event which has been in abeyance since 2019. Its generous conditions for top players are sure to attract a strong entry of grandmasters. It is also an opportunity for rising talents to showcase their skills, and for ambitious amateurs to take on, and perhaps surprise, highly rated opponents.

3846: 1...Nf4+! 2 Kg1 If 2 gxf4 Qg4+ 3 Kf1 Qxf3 and Rc1+ is a winning threat. Qh3! and Carlsen resigned faced with Qg2 mate or Rc1+.