This is a variant from the game Nana Dzagnidze v Valentina Gunina, Cairns Cup, St Louis 2020. Black has the brutal threat of Rh8, Qxh2+ and Rxh2 mate. Can you find Whites only move to escape?

Guildfords stranglehold on Britains Four Nations Chess League (4NCL) is set to continue for an eighth consecutive season as the Surrey club steamrollered two more opponents at Daventry last weekend, while their sponsored rivals from Yorkshire and the Isle of of Man lost ground on the leaders. Guildford last lost a match, 3.5-4.5 to White Rose, on 5 May 2012, since when the teams unbeaten run stretches to 81 wins and two draws.

Each of two sections qualifies four teams for the championship pool. Guildford lead the A group with 8/8 ahead of Chessable White Rose and Wood Green 6/8. The B group has Chess.com Manx Liberty 8/8, Grantham 7/8 and Guildford B 6/8. Guildford have won all four matches by at least 7-1 so are already well ahead on game points.

A mix of experienced English and French Olympiad grandmasters form Guildfords core and it was a specially good weekend for Michael Adams. The seven-time British champion is aged 48 and has recently struggled to hold on to the England No 1 spot against his younger rivals Luke McShane, Gawain Jones and David Howell. But Howell had a form dip at Hastings while Jones has been held back by draws, whereas in the last few weeks Adams scored an unbeaten 7/10 at Gibraltar, then defeated GMs Stephen Gordon and Jon Speelman at the 4NCL.

The Cornishman has now recovered not only his England No 1 position but also a 2700 elite rating and is the second oldest 2700+ after Indias former world champion Vishy Anand. Matthew Sadler, the England No 2 four rating points behind Adams, is co-author of Game Changer, the acclaimed AlphaZero book, and an amateur GM who plays little apart from the 4NCL yet hardly ever loses. In his game against 3Cs Sadler won what he later described as his most AlphaZero-like game yet.

It was also interesting that Guildford fielded the Leicester GM Mark Hebden on bottom board. Hebden, who will be 62 on Saturday, played a key, though understated, role in the 1970s and 80s boom when England for a few years became the No 2 chess nation after the Soviet Union. Many opening novelties worked out then were developed on the weekend circuit where few games were published and where Hebden evolved a purpose-built repertoire which made him a prolific prize winner.

The Grand Prix, Barry and 150 Attacks were his weapons, with easy to understand strategies which attracted a host of followers and are still popular among online blitz players. Hebden was at it again last weekend, where his opponent seemed unfamiliar with the 150 Attack and was crushed in short order.

Blacks 7 a6? (better c6 to secure d5 for the f6 knight) was far too slow and could already have been met by 8 e5!, but Hebden preferred the classical plan of switching his queen to boost his K-side attack. Then 12Nbd7? put Blacks minor pieces in a tangle, and the position fell apart.

Mark Hebden v Aisha Benhamida (Guildford v 3Cs)

1 d4 Nf6 2 Nc3 g6 3 e4 d6 4 Nf3 Bg7 5 Be3 0-0 6 Qd2 Nbd7 7 Bh6 a6? 8 0-0-0 Nb6 9 h3 Be6 10 Qg5 c6 11 Qh4 Qc7 12 Ng5 Nbd7? 13 f4 Rfe8 14 Bxg7 Kxg7 15 e5 Nh5 16 g4 h6 17 Nxe6+ fxe6 18 gxh5 1-0

When Manx unleashed Hungarys world No 14, Richard Rapport, against Guildford in last seasons final match, it seemed this might be a foretaste of a sustained title challenge. This has not happened yet, as both Manx and White Rose have relied on their pre-sponsor squads. The challenging pair are expected to make their effort at the final league weekend in May when they will probably bring in some overseas heavyweights, but it will be a slim chance. White Rose have already lost a match while Guildford are already virtually assured of superior game points.

Irelands Gonzaga, newly promoted from Division Two, and Scotlands Alba, newly relegated from Division One, are both effectively national teams, though far from full strength. Both have the same basic problem.Their squads are expert level with a sprinkling of masters, and this formula is insufficient for consistent survival in the top division, so both may be in a pattern of yo-yoing between divisions.

A former world champion in action in Division Two is a rare sight. Chinas Tan Zhongyi, fresh from winning the 20,000 womens first prize at Gibraltar, played No 1 for Kings Head, the London chess pub team, and won two smooth strategic games.

On the international front,the central action this week is at the Prague Masters including six GMs from the world top 30. Chess fans will be watching Alireza Firouzja,16, in his second elite tournament following Wijk aan Zee, where he was wiped out 5-0 by the super-elite but scored well against others.

3658 1 cxb4! draws. If Rh8 2 Qc6+! Kg7 3 Qc3+! Kg6 4 Qd3+! when Black must repeat by 4..Kg7 since 4f5? loses to 5 Qd6+! when the BK must self-block by Kh5 or be mated. The Cairns Cup of 10 top women players is the female version of the elite Sinquefield Cup, and its final rounds can be watched free and live online this weekend.

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Chess: Guildford extend unbeaten run to 83 matches over nearly eight years - The Guardian