Chess

Before getting embroiled in the games of the Karpov-Kamsky match (their past games have averaged around 70 moves each, incidentally), here's a nice short problem. Composed by Hans Rehm, it's White to play and mate in 11.

The first thing to notice is that 1.Nd3 is not mate because of Kxf3, but it would be mate if the f-pawn were defended. The second thing is that 1.Nd5+ Kf5 2.Ne7+ Kf6 3.Rg6 is mate, as is 2...Kf4 3.Ng6+ Kf5 4.Nh4+ Kf4 5.Nd3 mate. The only problem there comes after 2...Ke6, when Black escapes. But if the e6 square were blocked, it would all work well.

Finally, it is clear that White must do something quickly, or the black h-pawn will queen. Since 1.Rxh2 loses White's bind and lets Black escape with 1...Kg5, the first move must create a mating threat.

Combining those ideas, you should come up with 1.Ke2, defending f3 and threatening 2.Nd3 mate, but what to do after 1...Ba6+? After 2.Kf2, the black pawn promotes to a knight with check. Well the pawns on b4 and c3 must be there for a reason, so let's try 2.b5 Bxb5+ 3.Kd2. The threat is now 4.Rg4 mate, and 3...Nh6 is met by 4.Be7 followed by Bg5 mate. So the bishop must return with 3...Bd7. So what difference has that made? We can now play 4.Nd5+ Kf5 5.Ne7+ and since d7 is blocked, Black must play 5...Kf4 (Ke6 allows Rg6 mate). Now 6.Ng6+ Kf5 7.Nh4+ is met by 7...Ke6! so it's time for a repeat performance: 6.Ke2! Bb5+ 7.c4! Bxc4+ 8.Kd2! Be6 and finally 9.Ng6+ Kf5 10.Nh4+ Kf4 11.Nd3 mate.

Arts and Entertainment
Kirk Cameron is begging his Facebook fans to give him positive reviews
film
Sport
premier leagueMatch report: Arsenal 1 Man United 2
Arts and Entertainment
Jason goes on a special mission for the queen
tvReview: Everyone loves a CGI Cyclops and the BBC's Saturday night charmer is getting epic
Sport
Jonny May scores for England
rugby unionEngland 28 Samoa 9: Wing scores twice to help England record their first win in six
PROMOTED VIDEO
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

Day In a Page

Mau Mau uprising: Kenyans still waiting for justice join class action over Britain's role in the emergency

Kenyans still waiting for justice over Mau Mau uprising

Thousands join class action over Britain's role in the emergency
Isis in Iraq: The trauma of the last six months has overwhelmed the remaining Christians in the country

The last Christians in Iraq

After 2,000 years, a community will try anything – including pretending to convert to Islam – to avoid losing everything, says Patrick Cockburn
Black Friday: Helpful discounts for Christmas shoppers, or cynical marketing by desperate retailers?

Helpful discounts for Christmas shoppers, or cynical marketing by desperate retailers?

Britain braced for Black Friday
Bill Cosby's persona goes from America's dad to date-rape drugs

From America's dad to date-rape drugs

Stories of Bill Cosby's alleged sexual assaults may have circulated widely in Hollywood, but they came as a shock to fans, says Rupert Cornwell
Clare Balding: 'Women's sport is kicking off at last'

Clare Balding: 'Women's sport is kicking off at last'

As fans flock to see England women's Wembley debut against Germany, the TV presenter on an exciting 'sea change'
Oh come, all ye multi-faithful: The Christmas jumper is in fashion, but should you wear your religion on your sleeve?

Oh come, all ye multi-faithful

The Christmas jumper is in fashion, but should you wear your religion on your sleeve?
Dr Charles Heatley: The GP off to do battle in the war against Ebola

The GP off to do battle in the war against Ebola

Dr Charles Heatley on joining the NHS volunteers' team bound for Sierra Leone
Flogging vlogging: First video bloggers conquered YouTube. Now they want us to buy their books

Flogging vlogging

First video bloggers conquered YouTube. Now they want us to buy their books
Saturday Night Live vs The Daily Show: US channels wage comedy star wars

Saturday Night Live vs The Daily Show

US channels wage comedy star wars
When is a wine made in Piedmont not a Piemonte wine? When EU rules make Italian vineyards invisible

When is a wine made in Piedmont not a Piemonte wine?

When EU rules make Italian vineyards invisible
Look what's mushrooming now! Meat-free recipes and food scandals help one growing sector

Look what's mushrooming now!

Meat-free recipes and food scandals help one growing sector
Neil Findlay is more a pink shrimp than a red firebrand

More a pink shrimp than a red firebrand

The vilification of the potential Scottish Labour leader Neil Findlay shows how one-note politics is today, say DJ Taylor
Bill Granger recipes: Tenderstem broccoli omelette; Fried eggs with Mexican-style tomato and chilli sauce; Pan-fried cavolo nero with soft-boiled egg

Oeuf quake

Bill Granger's cracking egg recipes
Terry Venables: Wayne Rooney is roaring again and the world knows that England are back

Terry Venables column

Wayne Rooney is roaring again and the world knows that England are back
Michael Calvin: Abject leadership is allowing football’s age-old sores to fester

Abject leadership is allowing football’s age-old sores to fester

Those at the top are allowing the same issues to go unchallenged, says Michael Calvin