The Everest of chess problems

by Frederic Friedel
5/23/2023 – Exactly 70 years ago today, on May 29, 1953, the world's highest mountain, Everest, was climbed for the first time – a heroic feat, exuberantly celebrated by all. Today, hundreds scale the mountain each year. 40 years ago the Mount Everest of problem chess, the daunting Babson task, which for a century had seemed quite impossible to do, was mastered for the first time. Today new versions appear regularly. Here are some of the best. It's great fun checking the symmetrical underpromotions with an engine.

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Scaling the world's highest peak was considered a supremely daunting endeavour. In 1953 Edmund Hillary and Sherpa Tenzing Norgay succeeded in reaching the 29,035-foot summit of Everest, becoming the first climbers to do so. Today, in spite of its treachery, Everest is being climbed by affluent amateurs in great numbers. On the right is a genuine summit photo. 

The Baroque and Classic Babson

Five years ago I wrote about the Babson saga in my article "The perfect Babson" and "Revisiting Tim Krabbé and Babson").  

The "Babson" is a four-move chess problem in which all four promotions (to Q, R, B, N) of the same black pawn on the same square are followed each by the corresponding promotions (to Q, R, B, N) of the same white pawn on the same square (Echo-Babson).

In 1960, the French metallurgic engineer Pierre Drumare made a life-changing decision. He had composed many direct mates and fairy chess problems, and now decided to undertake what he called a "Search for the Impossible." He started to spend an average of four hours a day trying to compose a Babson problem. In 1982 he finally gave up. "After 22 years of exhausting labour I now have the certainty that the quadruple echo promotion will never be perfectly realised in a direct mate problem," he wrote.

In 1983 Leonid Vladimirovich Yarosh, a 26-year-old soccer and chess trainer from Kazan, who had previously published only three problems in Shakhmatny and in Thèmes-64, succeeded in composing three Babson problems! His second (August 1983) is quite magnificent, famous for its wonderful key move.

Note that in each of the following diagrams you can start an engine (fan button) and see how each promotion requires an echo promotion to the same piece to achieve a mate in the required number of moves. 

The solution, after the wonderful key 1.a7!, unfolds in four main lines:

1...axb1Q 2.axb8Q! Qe4 3.Rxf4/Qxf4 Qxf4 4.Qxf4/Rxf4#
1...axb1R 2.axb8R! Rxb2 3.Rxb3 Kxc4 4.Qa4#
1...axb1B 2.axb8B! Be4 3.Bxf4 Bxa8 4.Be3/Be5#
1...axb1N 2.axb8N! Nxd2 3.Qc1 Ne4 4.Nc6#; or 3...N(any) 4.Rxf4#.

These are the four thematic variations which form the main lines. Unfortunately, a dual exists in the queen variation (3.Rxf4,Qxf4) and in the bishop variation (4.Be3#,Be5#). Besides there are several fine four-move side lines, e.g. 1…Qe5/Qxd8+/Qd6/Qxa8, some with duals. 

Note: in 1983 engines for solving chess problems did not yet exist. Today you can experiment directly on the diagram above: click on the fan button to start an engine and then try all the lines given above. You will see that after each black promotion the corresponding white promotion is required in order to complete the mate in four moves. 

To date around 30 Echo-Babson problems have been published, but none in which the four main lines as well as the four-move side lines have all been free of duals. That would be the perfect Echo-Babson. For its first realization problemist Werner Keym offered a prize of 100 Euro in 2010.  

For anyone interested in delving deeper into the subject we can recommend the excellent (German language) treatise by Peter Hoffmann and Erk Zierke in “100 Years: Babson task in the Orthodox Directmate.” It is 146 pages long (!) and discusses different versions of the Babson task, and especially on pages 26-47 and 136-139, all currently known examples of the Echo-Babson. The foreword of the paper and the solutions (and positions in text format) are in English.

In 1986 Peter Hoffmann composed the first Babson problem with dual-free main lines:

The key move, however, is obvious: 1.dxe7!

1… e1Q 2.exf8Q! Qxe4+ 3.d4 Qf5 4.Bxf5#
1… e1R 2.exf8R! Rxe4+ 3.d4 Kg7 4.R4f7#
1… e1B 2.exf8B! Kg8 3.Qa6 Kh7 4.Qg6#
1… e1N 2.exf8N! Kg8 3.Ka5 N~ 4.Qc4#

There are several four-move side lines, e.g. 1…Re8/Rg8/Rxf4/Rf6/exd1Q/exf1Q, mostly with duals.

To date there are eight Babson problems with dual-free main lines, two of them are recent ones by Leonid Yarosh (2022) and Werner Keym (2023).

Here Black threatens with 1…fxe1Q+. The key move 1.Qd1! is good for it:

1…g1Q 2.gxf8Q! Qxg6 3.Be4 Qxe4 4.Qg7#
1…g1R 2.gxf8R! Rxg6 3.Qc2 Kh6 4.Qxg6#
1…g1B 2.gxf8B! Kh8 3.f7 Kh7 4.Rh6#
1…g1N 2.gxf8N+! Kh8 3.f7 Nxe2+ 4.Nxe2#

There are several four-move side lines, e.g. 1…Qc8/Qg8/Qc5+/gxf1Q/gxh1Q, some with duals.

The tries 1.g8Q,g8R,g8N+? are followed by 1…Kxf5! and 1.Be6? by Kxg7!. The special try 1.Nxh6? seems to be successful, but it is refuted by the ‘underpromotion’ 1…d1N!.

The key move is 1.g4! 

1…d1Q 2.g8Q! Qxd4+ 3.c4 Qxb2 4.Qg6#
1…d1R 2.g8R! Rxd4+ 3.c4 Kxf7 4.Rdf8# 
1…d1B 2.g8B! Kg7 3.c4 Kf6 4.d5#
1…d1N 2.g8N+! Kg7 3.f6+ Kh7 4.Bxc2# 

There are only two four-move side lines: 
1…Kxg7 2.f6+ Kxf6 (2…Kh7? 3.Rh8#) 3.Rg8 ~ 4.Rg6# 
1…dxc1Q? 2.g8Q,g8R (dual) Qa1+ 3.Bxa1 ~ 4.Qg6#,Qh8#,Rg6#. That is only a so-called “minor dual” since after 1.g4! White threatens to play 2.g8Q,g8R and 3.Qg6#,Qh8#,Rg6# and Black’s defense 1…dxc1Q? proves ineffective because it only delays the end (4.Qg6#,Qh8#,Rg6#). 

Among the 30 Echo-Babson problems this one has some unique selling points:

  • in the initial position there is no black officer (Q, R, B, N) at all;
  • a special try exists (1.Nxh6? d1N!);
  • the main lines start with three pawn moves without any capture (1.g4 d1X 2.g8X);
  • there is only one “minor dual” in a side line (1.g4 dxc1Q? 2.g8Q,g8R). 

When you compare Leonid Yarosh’s complex Babson from August 1983 with Werner Keym’s simple Babson from 2023 you may call the former “The Baroque Babson” and the latter “The Classic Babson”.

Octogenarian puzzle master -Werner Keym is a teacher (of French and Latin) and a musician who has organised more than 300 concerts in his town. In 2010, he ran for Mayor of Meisenheim and won in a landslide. Now in retirement he devotes his time to the family — he has six grandchildren — and to his hobbies. The foremost of them is problem chess, where he is the is one of the most creative problemists we know. He specializes in puzzles involving castling, en passant captures and pawn promotion. Here are articles by or about Werner Keym.

Editor-in-Chief emeritus of the ChessBase News page. Studied Philosophy and Linguistics at the University of Hamburg and Oxford, graduating with a thesis on speech act theory and moral language. He started a university career but switched to science journalism, producing documentaries for German TV. In 1986 he co-founded ChessBase.