Benko: Fun problems to celebrate the day

by GM Pál Benkö
4/4/2014 – Our friend and world famous chess composer GM Pal Benko got into the spirit of the day and sent us three problems to solve. They look deceptively easy, but you must consider the day of publication and not be fooled by the guile of the composer. We will leave you to work things out for a few days, and then give you the answers which may come as a surprise to some. [Now with solutions!]

Fun problems for April 1st

By Pál Benkö

Here are some problems to celebrate the day. Be careful, they are not quite as easy as they seem!

Mate in one move

Is this checkmate? Can Black play ...hxg3 e.p.?

Black has just played his king from g8 to h8. But how could this be legal?
And is the position stalemate or can White win?


Thanks for the many letters, which showed us how entertaining the little puzzles by Pal Benko had been. Unfortunately we did not switch off the comments at the bottom of the page, so the solutions were quickly revealed to subsequent visitors. Here they are in full.

Pal Benko, 2014

Mate in one move

We must confess that we forced Pal to simplify a much more sophisticated version of the above idea, to give the puzzle a touch of an April Fool's prank. The position is indeed mate in one, but if you look at it carefully you will see that Black has no last move (...Bg3-h2 is impossible since the white king would have been in check). So it must be Black to move and the solution is 1...Kxg2 mate.

Pal Benko, 2014

Is this checkmate? Can Black play ...hxg3 e.p.?

It would only be checkmate if Black could not capture en passant. But if the white pawn had been on g2 before the last move, then Black has no previous move. The only possibility is that the white pawn moved to g4 either from g3 or from f3. In the first case the white bishop could have been on f1 or g2 and the black king on g4. White played 1.Bh3+ and Black replied 1...Kh5, after which White could deliver mate with 2.g3-g4#. The other possibility was that the white pawn on fd3 captured a black piece that had move to g4 on the previous move. So yes, the position is a legal checkmate, and Black cannot play ...hxg3 e.p.

For the third puzzle we must assume that the position before the diagram above had a knight on f7, which makes the position legal. The rest is a very nice study by Pal Benko.

[Event "?"] [Site "?"] [Date "2014.??.??"] [Round "?"] [White "Benko, Pal"] [Black "White to play and win"] [Result "1-0"] [SetUp "1"] [FEN "6k1/5Np1/6P1/8/8/8/B7/KN6 w - - 0 1"] [PlyCount "35"] 1. Nh8+ Kxh8 {This is the puzzle position.} 2. Bg8 $1 Kxg8 3. Nc3 Kf8 4. Nd5 Ke8 5. Kb2 Kd7 6. Nf6+ $1 Ke6 7. Nh7 $1 Kf5 8. Nf8 Kf6 9. Kc3 Ke7 10. Nh7 {etc. :} Ke6 11. Kd4 Kf5 12. Nf8 Kf6 13. Ke4 Kg5 14. Ke5 Kh6 15. Ke6 Kg5 16. Kf7 Kh6 17. Kg8 Kg5 18. Kxg7 {and wins.} 1-0

Some earlier ChessBase articles on Pal Benko

3/29/2014 – Pal Benko on Richard Réti’s endgames (2)
125 years ago a boy was born in the Austro-Hungarian part of what is today Slovakia. Richard Reti was a mathematician and world class chess master. Reti was also an endgame specialist who composed some of the most original endgame studies ever devised. Some were flawed, and now, almost a century later, his compatriot GM Pal Benko provides revisions to these studies.

3/26/2014 – Pal Benko on Richard Réti’s endgames (1)
At the turn of the last century an Austro-Hungarian mathematician shook up the chess world with revolutionary new ideas ("hypermodernism"), and with some of the most original endgame studies ever devised. To celebrate his upcoming 125th birthday another great chessplayer and endgame specialist, GM Pal Benko, has sent us some examples of Reti's works.

12/23/2013 – Pal Benko: Secrets of Study Composition (2)
One of the greatest study composers – as well as a former world championship candidate – is our friend Pal Benko, who never fails to send us a special Christmas gift. This year it was an article that offers unique insight into the process of chess composition. We brought you the first part a week ago. Today it is about breaking the pin and avoiding stalemate. And there is a remarkable study for you to solve.

12/17/2013 – Pal Benko: Secrets of Study Composition (1)
There is more to chess than tournament games. The area of chess studies and problems is equally creative and breathtakingly imaginative. One of its greatest composers is grandmaster (and world championship candidate 1959 + 1962) Pal Benko. The 85-year-old author of some of the most famous studies of all time has sent us an essay on the remarkable process of chess composition.

7/15/2013 – The Life Gambit à la Benko
Pal Benko (Hungarian: Benkö Pál) is, as 99% of our readers probably know, a legendary chess grandmaster, author, and composer of endgame studies and problems. He was born on July 15 1928, which made him 85 today. Diana Mihajlova met the fit and active octogenarian, who has been a "pal" of our company for a decade, in his home town of Budapest. Here is part one of her birthday report.

7/18/2013 – The Life Gambit à la Benko – Part two
On Monday Pal Benko, legendary grandmaster, author, and problem composer, turned 85. Diana Mihajlova, who recently met with the fit and active octogenarian in his home town of Budapest, sent us a birthday report in two parts. Today we learn of Benkos escape from Communist Hungary to the US, and his relationship with Bobby Fischer. And we get to solve two highly entertaining problems.

5/20/2011 – Greetings from Pál Benkö for 25 years of ChessBase
"Congratulations to ChessBase on your 25th anniversary! Your news page is the the first thing I look at every day when I go on the Internet. You do such wonderful work. Keep up your great service for the whole chess world." Heartening words from legendary great chess player, theorist, author and problem composer – who in addition sent six anniversary puzzles for our readers.

4/24/2011 – Easter puzzles by Benko – a World Champion challenge
Pál Benkö, 82 and still going strong, is a world class grandmaster, author and problem composer. He is also a faithful friend who periodically sends us puzzles for our newspage. This time, for Easter, he has selected four problems which stumped a World Champion. It is a challenge for you to do better, and win a special prize in the process. Enjoy.

12/30/2009 – Pal Benko improves on Troitzky
In 1856 the great Sam Loyd composed a chess problem, which 75 years later inspired Alexey Troitsky, one of the greatest composers of endgame studies, to create a puzzle with a similar theme. It proved to be flawed. 75 years after Troitzky another great composer, Pal Benko, took up his problem, improved on it and submitted it for our Christmas Puzzle page.

Topics problems, Benko

World class chess grandmaster, author, and composer of endgame studies and problems. Benko qualified for the Candidates Tournament for the World Championship in 1959 and 1962, and for the 1970 Interzonal tournament, when he gave up his spot to Bobby Fischer, who went on to win the World Championship in 1972. Pal was born in 1928 and lives in Budapest, Hungary.
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The_Phenom The_Phenom 4/2/2014 12:48
Let me give you my answers.
(1) ...Kxg2 mate
(2) Yes, its a checkmate. If white's last move was "g2-g4", there would have been no legal move for black that it could have played before "g2-g4". Therefore white's last move must have been "f3xg4" or "g3-g4".
(3) The last moves were, 1.g6+(or f5xg6+)-Kh8 (which gives us the current position) 2.Bg8
McUH McUH 4/2/2014 01:42
This is not related to solution itself, so I hope it does not spoil it for others. Can white really win in the 3rd diagram?
The_Phenom The_Phenom 4/2/2014 02:18
Yes, of course. Although, it does need and accurate play from white side, but it is a winning position. You can check it through the endgame tablebase. Link:
McUH McUH 4/2/2014 03:15
Thanks for the interesting link. I missed the Nd5-f6 trick...
Henk-Jan Paalman Henk-Jan Paalman 4/2/2014 04:10
"(3) The last moves were, 1.g6+(or f5xg6+)-Kh8 (which gives us the current position) 2.Bg8 "

It is also possible that white's last move was Nf7-h8+. After which black played Kg8xh8.
The_Phenom The_Phenom 4/2/2014 06:33
Yes, definitely.
MJFitch MJFitch 4/2/2014 07:58
#1 Mate in one move. If white moves first 1.Qf2# If black moves first 1...Kg2#
#2 is this checkmate? ((( Yes ))) Can black play ...hxg3 e.p.? Only if whites last move was g2-g4
#3 Black has just played his king from g8 to h8. But how is this possible? 1.Nf7-h8+ Kxh8!!
And is the position stalemate or can white win? White wins 1.Bg8! Kxg8 2.Nc3 kf8 3.Nd5! Ke8 4.Kb2 Kd7 5.Kc3 Ke6 6.Kd4 Kf5 7.Ne7 Ke6 8.Nc6! Kf6 9.Ne5 Ke6 10.Ke4 Kf6 11.Kf4! Ke6 12.Ng4 Ke7 13.Ke5 Kd7 14.Nh6! Ke7 15.Nf5 Kf8 16.Ke6 Kg8 17.Ke7 Kh8 18.Nh6!! gxh6 19.Kf7! h5 20.g7+ Kh7 21.g8=Q+ Kh6 22.Qg6#
Henk-Jan Paalman Henk-Jan Paalman 4/2/2014 08:51
What McUH meant was:

1.Nh8+-Kxh8 2.Bg8-Kxg8 3.Nc3-Kf8 4.Nd5-Ke8 5.Kb2-Kd7 6.Nf6!!

6. ...-gxf6 7.g7 +-
6. ...-Ke6 7.Nh7-Kf5 8.Nf8 +-
MarinVukusic MarinVukusic 4/2/2014 10:32
The trick is always to figure out the only way the position could have been reached.

1) Only possible solution is 1... Kg2#
2) Checkmate, unseen move is 1. Bf1-h3+, Kg4 and now 2. g3-g4#
3) Unseen move is 1. Nf7-h8+, Kh8 and now 2. Bg8, Kg8; 3. Nc3, Kf8; 4. Nd5, Ke8; 5. Kb2, Kd7; 6. Nf6!! and the rest is easy.
Grokon Grokon 4/3/2014 03:54
2) White did not play g2-g4 or g3-g4 because Black could not have moved earlier. White played f3xg4, taking a black piece. So no prise en passant.

Same thing in 1) Only Black can mate. If it was White to move, Black cannot have made the last move in this position.
The_Phenom The_Phenom 4/3/2014 04:18
No. Black could have played g3-g4. In such case, black's last move will be Kg4(under check) to Kh5. 1.Bg2(or f1)-h3+, Kg4-h5 2.g3-g4 mate
Vic Fontaine Vic Fontaine 4/3/2014 07:38
3) 1.Bg8! (avoiding stalemate) 1. ... Kxg8 (only move) 2.Nc3 Kf8 3.Nd5! (W controls e7-f7-squares, forcing a longer path for B's K) 3. ... Ke8 4.Kb1! (zugzwang) 4. ... Kd7 5.Nf6+! Ke7 (5. ... gxf6 6.g7+-) 6.Nh7! (W controls f6-f7-squares) 6. ... Ke6 7.Kb2 Ke5 8.Kc3 Kf5 9.Nf8 Kf6 10.Kd4 Kf5 11.Kd5! (opposition) 11. ... Kf6 12.Kd6! Kf5 13.Ke7+-, and W's K captures Pg7 and then drives Pg6 to promotion
Victor Lee Victor Lee 4/3/2014 07:43
The_Phenom is correct.

One possible starting position for puzzle 2 is:

White: Kf7, Bh6, g5, g3, Bf1
Black: h4, Kf3

This is a legal position. Black then starts the following sequence: Kg4 Bh3+ Kh4 g4#. Remember, black doesn't have to play "intelligently" in these puzzles. en passant is impossible. There is no starting position that would have led to that end position as far as I can find (play/solve backwards). The key here being that the bishop would not be able to access h3 given the block of the pawn on g2 if the bishop starts on the f1-h3 diagonal. If on the h3-c8 diagonal, it is not clear how black would easily have made it to h5 given the double coverage of g4 from the bishop and the pawn on f3.

Puzzles 1 (depends on whose move) and 3 (Nf7-h8) are pretty straightforward.
Jorge Shinozaki Jorge Shinozaki 4/4/2014 11:01
If the first problem is a checkmate problem, it is very easy that a beginner can solve it quickly.
So. I guess "Mate in one move" means "Stalemate in one move" or "Helpmate in one move." Right?
MarinVukusic MarinVukusic 4/4/2014 03:13
Well it is easy if you realize that there is no way Black could have moved last.
al F al F 4/4/2014 10:02
(3) The winning line for White is very nice, and I'm proud that I found it. But the position is a draw!

Black can't win and has no need to chase the White pawn. So just moving back and forth between g8 & h8 there's no way for White to get a winning capture at g7.
MarinVukusic MarinVukusic 4/5/2014 03:58
Nope, White paralyzes the Kh8 via Nf6 and then after gf6 he plays Kf7 and wins easily.