Walkabout >
Walkabout 2017 < Prev | Next >
Chess and problem rambles by PW

2 Feb. 2017 – Two selfmates by Laimons Mangalis

In December’s column regarding a new e-book on Laimons Mangalis, I mentioned that he was a proficient composer of selfmates. Since this major problem genre is rarely discussed on this site, it seems a good opportunity to delve into some examples discovered in the book. In selfmates, White plays first and compels Black to mate in the specified number of moves, while Black does not cooperative and resists giving mate. The two selections below are both fine illustrations of the type, presenting appealing and accessible ideas.

Laimons Mangalis
The Problemist 1977
Selfmate in 2

In the first problem, Black’s B + K battery pointed at the white king suggests that it will be forced to open and deliver mate at some stage. Hence if Black were to play 1…Sf3 guarding e5 and d4, then 2.Qg7+ Kxg7 mate. This is the only set variation, however, as no selfmates-in-one are prepared for the other black moves. Consider the checks 1…Kf8+ and 1…e6+; each by attacking d5 means that 2.Ke5 could be followed by 2…Sf3 mate, but Black is not obliged to move the knight. The key 1.Qh8!, a waiting move, deals with these checks because: (1) 1…Kf8+ now self-pins the black bishop (and also the e7-pawn), so that 2.Ke5 does force 2…Sf3 by zugzwang, and (2) after 1…e6+ 2.Ke5, the black king is confined by the queen from its corner position, leaving 2…Sf3 again as Black’s only legal move. The black royal battery fires twice as the mating move: 1…Sf3 2.Qg7+ Kxg7 as in the set play, and 1…e5 2.Qf6+ Kxf6, when White makes a different queen sacrifice to ensure that the black king covers the e5-flight.

Laimons Mangalis
The Problemist 1977
Selfmate in 2

The second position contains a R + B battery on the first rank, and any bishop move would mate immediately. A set line utilises the battery thus: 1…Ke3 – attacking f2 – 2.Rxe4+ Bxe4. The surprising key 1.Kh1! (waiting) unpins the queen, sparking a full-length variation when Black moves the bishop: 1…B~+ 2.Qg1+ Rxg1. The black king has two flights on e3 and c5. Taking the first gives 1…Ke3 2.Rxe4+ Bxe4 – unchanged from the set play, though here the queen is pinned on the diagonal instead. If Black takes the second flight, White exploits the unpin of the black knight with 1…Kxc5 2.Qf2+ Sxf2. The final defence 1…c2 admits 2.Qxc2, immobilising the black king, and Black is forced by zugzwang to open the R + B battery once more: 2…Bxc2.

20 Mar. 2017 – ‘J. K. Heydon: Problemist, Solicitor, Businessman’

Bob Meadley’s excellent series of e-books continues with the publication of J. K. Heydon: Problemist, Solicitor, Businessman. Joseph Kentigern Heydon (1884-1947) was a leading Australian problem composer who produced mostly traditional two- and three-movers. He was especially skilled in devising mutates (fashionable in his era) and task problems. This volume begins with a biographical chapter that describes Heydon’s multifaceted life as a scientist, solicitor, and author of religious books. His chess activities are then reviewed, and the next chapter covers his stint as the problem editor of the Australasian Chess Review. A “Notes and Scans” section reproduces a variety of materials, such as his entry in Who’s Who in Australia and a letter to the British Chess Magazine that indicates he pioneered a variation of the Evans Gambit. The book concludes with a collection of 62 problems by Heydon; reflecting the difficulties in gathering materials from the early 20th century, Bob mentioned that this is not Heydon’s complete output.

Joseph Heydon
Australasian Chess Review 1932
International Tourney, 2nd Commended
Mate in 2

Here are two selections from the e-book, which can be downloaded using the link above. The first two-mover shows correction play by three black pieces, unified by White’s self-interference mates that are made possible by Black’s self-blocks. The key is 1.Be7! (waiting). 1…B~ 2.Sb3, 1…Bc4 2.Sc6, 1…Bxd5 2.Bc5; 1…Sd~ 2.Qc3, 1…Se3 2.Sf3; 1…Sf~ 2.Rd3, 1…Se4 2.Sf5. The judge J.J. O’Keefe commented, “This achieves white interference on four lines with consummate ease and artistry.”

Joseph Heydon
Good Companions 1921
Complete Block Tourney, 2nd Prize
Mate in 2

Two of Heydon’s compositions are cited in Jeremy Morse’s seminal Chess Problems: Tasks and Records. One appeared previously on this site as a weekly problem, No.295. The other is a modified version of the above two-mover, which brings about a remarkable five changed mates in mutate form. Set mates are prepared for all of Black’s moves: 1…Bb7 2.Qxd7, 1…S~ 2.Qxc5, 1…b3 2.c4, 1…c4 2.Bxc4, 1…g~ 2.Bc4, and 1…e4 2.Sf4. The flight-giving key 1.Se4! (waiting) removes the latter variation but adds another one, 1…Kxe4 2.Qc6. The remaining play is completely changed: 1…Bb7 2.Qxb7, 1…S~ 2.Sf6, 1…b3 2.Sc3, 1…c4 2.Qxc4, and 1…g~ 2.Qd6.

30 Apr. 2017 – Norman Macleod Award winner and cyclic shift

The Norman Macleod Award, organised by the British Chess Problem Society, is bestowed on the most striking and original problem of any genre published in The Problemist over a two-year period. Given its emphasis on novelty, perhaps it’s not surprising that the Award had never been won by any two-movers, the most highly investigated of all genres. However, in the recently announced Award for the 2014-15 period, the Slovakian Grandmaster Peter Gvozdjak has managed to break the trend, by gaining first place with a brilliant two-mover. His problem realises for the first time a theme described as “fourfold cyclic shift in threat form” – a complex type of changed play. Before analysing it, though, I should provide an example of a two-mover showing the more standard form of cyclic shift.

Michel Caillaud
The Problemist 1981
2nd Commendation
Mate in 2

A cyclic shift of mates is a kind of extension of the reciprocal change scheme. The latter involves set or try play where the defences 1…a and 1…b are answered by 2.A and 2.B respectively, but after the key, the white moves are switched: 1…a 2.B and 1…b 2.A (examples: No.10, No.334). The two elements of play that get exchanged here – a pair of white mates – are increased to three or more elements in a cyclic shift to generate this “circular” pattern: 1…a 2.A, 1…b 2.B, 1…c 2.C in the set or try play, becoming 1…a 2.B, 1…b 2.C, 1…c 2.A in the actual play. This difficult idea, also called the Lacny theme, is accomplished very economically in the problem above. The try 1.Rh4? (waiting) prepares to attack f4 if Black moves the knight and also to pin the piece if the king takes the flight: 1…S~ [a] 2.Sh7 [A], 1…Kf4 [b] 2.Be3 [B], 1…B~ [c] 2.Qxg4 [C], but 1…Be6! defeats the try. The key 1.Rf7! (waiting) again aims for f4 but exploits the black bishop’s position instead, and the rook also covers f6 while unguarding h6. Now we see three changed variations where the same mates reappear but are shifted to other defences: 1…S~ [a] 2.Be3 [B], 1…Kf4 [b] 2.Qxg4 [C], 1…B~ [c] 2.Sh7 [A].

Peter Gvozdjak
The Problemist 2015
Norman Macleod Award 2014-15
Mate in 2

The Award winner demonstrates a fourfold cyclic shift as it contains a similar pattern but with four thematic defences and mates. Such a scheme is rarer but not new; what’s new is the form of that cyclic play, viz. the four mating moves are multiple threats, which are then separated or uniquely forced by the four defences. In the initial position, the g2-bishop and a5-rook are both controlling a potential flight on d5. Each of these line-pieces is cut off in turn by the d4-knight with the try 1.Sf3? and key 1.Sb5! Both knight moves create these four threats: 2.Qg8/Sxb2/Qd4/Qc3. The four thematic defences all take place on f3 and b5 – the same squares visited by the white knight – so that Black either (1) closes the remaining white line of guard to d5 or (2) captures the knight and removes its control of d4. All of these strategic effects – and more! – are designed to make each black defence foil exactly three of the four threats while leaving the fourth viable. Thus the try 1.Sf3? gives 1…Sb5 [a] 2.Qg8 [A], 1…Qxf3 [b] 2.Sxb2 [B], 1…Rb5 [c] 2.Qd4 [C], 1…Sxf3 [d] 2.Qc3 [D], but 1…Rxd1! refutes. Among the many dual avoidance effects, note for instance how 1…Sxf3 pins the d1-knight and prevents 2.Sxb2. After the key 1.Sb5!, every defence remarkably stops a new triplet of threats to bring about these cyclic changes: 1…Sxb5 [a] 2.Sxb2 [B], 1…Qf3 [b] 2.Qd4 [C], 1…Rxb5 [c] 2.Qc3 [D], 1…Sf3 [d] 2.Qg8 [A]. An amazing fusion of cyclic shift, Fleck theme (separation of threats), and dual avoidance, this two-mover really pushes the envelope!

4 Jun. 2017 – ‘Gordon Stuart Green: A Brilliant All-Rounder’ and ‘Some Mosely Material’

Gordon Stuart Green (1906-1981) was an Indian-born British problem composer who settled in Australia from 1966. “As GSG lived in Australia for 15 years we can claim him as ours!” writes Bob Meadley, who has put together an e-book about this “mental giant,” entitled Gordon Stuart Green: A Brilliant All-Rounder. Compared with earlier books in the series about more prominent composers, this is a relatively small collection of materials, totalling 30 pages. An introductory article provides some background information on Green – an accountant by profession and also a first-class sportsman – and indicates his strengths as a problem solver and composer, with two of his directmates examined. While he wasn’t prolific, the excellent quality of his problems makes up for the quantity, and the next chapter features eight of his compositions that I had selected. A “Scans and Notes” section follows, comprising a biographical piece by an Indian problemist, and various letters and articles by Green. Some non-chess related materials are included as well to show his wide range of interests, such as his technical notes on a Scientific American article and two of his brain-teasers. This free e-book can be downloaded using the link above.

Gordon Stuart Green
FIDE Tourney 1959
4th Hon. Mention
Mate in 4

Here is one of Green’s best problems, a four-mover that delivers a startling number of classical themes. The key 1.Bh7! vacates b1 to threaten 2.Bxa7 and 3.Qb6 – a Bristol manoeuvre – followed by 3…B~ 4.Qb1. If 1…g3, aiming for stalemate after 2.Bxa7?, then 2.Bb6 axb6 3.Qxb6 Bf2 4.Qb1. After 1…gxh3 (which cleverly defeats the threat by exploiting the white king’s position: 2.Bxa7? hxg2 3.Qb6 g1(Q)+), White executes another Bristol on the g-file with 2.Rg7 h2 3.Qg6, and then 3…Bxf2 4.Qb1. This variation reveals that the bishop-key is a clearance move that allows the queen to travel on the same diagonal line but in the opposite direction – a Turton doubling. Finally, 1…gxf3 is answered by 2.Rg6, which interferes with the key-bishop and forces 2…Kc2 3.Rb6+ Kd1 4.Rb1. Thus the key is also a critical move going across g6, and with the subsequent interference on that square to avoid stalemate and the firing of the created battery, the Indian theme is effected.

Just over a decade ago, Geoff Foster and Bob Meadley collaborated on an important two-part article, ‘Arthur Mosely and the Brisbane Courier’ (accessible from the Problemists and History section of this site). Bob has now produced a document about the research process that lies behind the article, named ‘Some Mosely Material’. It includes correspondence between Geoff and Bob detailing their thoughts on the project, preliminary versions of the article, and additional scans of Mosely-related images that didn’t make the final version. This interesting “behind the scenes” look at a great Australian problemist is available upon request.

5 Jul. 2017 – A tribute to Raymond Smullyan (1919-2017)

The logician and mathematician Raymond Smullyan passed away in February this year, at the age of 97. An astonishing polymath, he gained a PhD in mathematics and was additionally a philosopher, pianist, and magician. He was also an expert on Eastern mysticism, and I briefly discussed his spiritual philosophy in an earlier Walkabout column (12 Dec. 2012). To the general public, he was perhaps best known for his books of logical puzzles, the first of which was titled, What is the Name of this Book? But chess enthusiasts will remember him most for two collections of retro-analytical problems, The Chess Mysteries of Sherlock Holmes (1979) and The Chess Mysteries of the Arabian Knights (1981).

The Chess Mysteries must be among the most popular books on chess problems ever published. Smullyan wrote in an appealing style and the problems are accompanied by engaging storylines. The retros themselves – in which the tasks involve working out certain facts about the past of a diagram position – are proficiently devised, with a range of difficulty levels. Naturally the two volumes are fine introductions to the genre, and indeed Sherlock Holmes inspired me to create my first retros more than thirty years ago.

Raymond Smullyan
The Chess Mysteries of Sherlock Holmes
Black to move.
Can Black castle?

Here are two illustrations of Smullyan’s works. The first is quite straightforward, or “elementary” as Sherlock Holmes would say. Given it’s Black to move in the diagram position, is it legal for that player to castle? To answer this, we try to determine what occurred in the last few moves. White made the last move and it was Pa3, and just before that Black must have made a capture, because otherwise White would have no free unit with which to make a further retraction. The captured piece was one of the knights, since the only other missing white units are the rooks which couldn’t have escaped from the first rank. This white knight wasn’t captured by any of the pawns (none of which has a legal diagonal retraction), so it was captured by one of the four black pieces on the top rank. The a8-rook couldn’t have made this capture, however, because the uncaptured white knight on a8 would have no possible prior move. Likewise, if it were the c8-bishop which had captured the knight, then the latter on c8 could only have just come from the empty square d6, but such a retraction would be impossible because it implies that Black was in check by the knight on d6 while it was White’s turn to play. Therefore only the black king or the h8-rook could have captured the knight, which had come from d6 (to e8) or g6/f7 (to h8). That proves Black had previously moved the king or the h8-rook in the game, and now cannot castle.

Raymond Smullyan
The Chess Mysteries of the Arabian Knights
Neither king has moved.
Which white rook is the promoted one?

The second problem is more complex but still not exceedingly difficult. Which of the three white rooks is promoted? Solving this requires dealing with a couple of preliminary questions. The first is: on which square did White’s missing e-pawn promote to a rook? Black has three missing pieces (rook, bishop, and knight) that were available for the e-pawn to capture on its way to the eighth rank. A rook promotion on the queen-side or the middle files wasn’t possible, however, because we are given the condition that neither king has moved, and such a promoted rook could not have left the top rank without dislodging the black king from e8 (e.g. by checking from d8). That means the e-pawn could only have promoted on h8 and the rook escaped via h6. The second preliminary question is: how did the d7-rook reach its current position? I shall leave the reader to answer that and solve the remainder of the problem!

13 Aug. 2017 – Kamikaze Chess

Fairy chess problems are akin to fantasy fiction and other genres of non-realistic stories in which “impossible” things occur. Such problems may employ unorthodox pieces (for example, the previously introduced grasshoppers and nightriders), which are analogous to imaginary beings with special powers. Another major type of unorthodox element – one that hasn’t been examined on this site before – is the fairy condition, which refers to an unconventional rule of play. Applying such a condition to a problem is rather like changing the laws of physics in a science fiction tale. In both cases we are asking, “What if?”, meaning we want to explore the interesting effects and consequences of modifying certain rules.

Myriad fairy conditions have been invented, varying in complexity and the degree to which they deviate from the regular game. One of the simplest is Kamikaze Chess. In this variant, when a capture occurs, both the capturing and captured pieces are removed from the board. Only the kings are exempt from this rule and they capture normally. What kinds of effects are possible with this condition? One basic way to exploit the rule is to utilise captures as a line-opening device – that is, a player can instantaneously open a line blocked by an enemy unit by capturing it. This tactic is used repeatedly in the two Kamikaze helpmates below.

Peter Wong
Problemkiste 1999
Helpmate in 2
Twin (b) Pb3 to b4

The first position has a pair of R + B batteries aimed at the black king, but two orthogonal flights must be covered and further, the black knight is poised to counter either rook check and it cannot move without yielding a third flight. The only way to deal with these hurdles is for White to deliver a double-check(mate) with the two rooks, achievable if the battery-firing bishop were to capture a black piece standing on the other rook line. Two additional line-opening captures are needed to set up such a double-check, which is obviously impossible in orthodox chess: 1.Q*e7 B*b3+ 2.Ra3 B*a3 (an ‘*’ designates a fairy capture). The twin (b) produces similar play: 1.R*f7 B*g7+ 2.Qg8 B*g8. The two white bishops reverse their roles and so do the black rook and queen. There’s also a reciprocal relationship between the a2-bishop and f3-rook in that each piece sacrifices itself to open a line for the other, and likewise for the f8-bishop and g5-queen.

Peter Wong
Problem Observer 1999
1st Prize
Helpmate in 2
2 solutions
(b) Sb8 to b1

The next problem comprises four phases of play that revolve around the two arranged pins. The solutions all entail organising a mate along one of the initial pin-lines, with the other pin required for the mate. First, the h6-rook can mate if the queen is allowed to open the h-file with a sacrificial capture: 1.Sd7 Qc5 2.S*e5 Q*h5. Second, the queen is given access to the potential mating square c8 by 1.S*c6, but now if White clears the diagonal with 1…B*g4?, Black will have no waiting move available to permit the queen mate. Instead, the unpin 1…Bg8 enables the black rook to remove itself with 2.R*g8, so that it cannot spoil 2…Qc8 with a switchback. The two solutions in part (b) closely match those in (a), and for each respective pair the strategic effects undergo an orthogonal-diagonal transformation. 1.Sc3 Qd1 2.S*e2 Q*g4 and 1.S*d2 Rg6 (not R*h5?) 2.B*g6 Qh6. The problem thus illustrates the Helpmates of the Future scheme in which two pairs of corresponding solutions are brought about.

3 Sep. 2017 – Weekly Problems and Walkabout archives

This site has been given a minor revamp. The Weekly Problems and Walkabout columns now have their own top-level main pages, reflecting the amount of contents in these sections. The Weekly Problems archive, besides providing links to all the relevant sub-pages, includes an index of composers. The Walkabout archive lists all of the columns in reverse chronological order. I have revised many of the columns’ subject headings so that they are more descriptive; particularly, the not-very-informative “What’s New” headings have all been replaced. A few improvements have also been made to the site’s design, including the sidebar with smaller icons and additional links on the home page. Further, there’s now a search box on every page in the footer section.

The xkcd comics only infrequently feature a chess topic, but I always enjoy them when they do appear, and here’s a good one I haven’t quoted before.

8 Oct. 2017 – The le Grand theme – Part 1

The le Grand theme, named after the Dutch brothers Henk and Piet le Grand who developed it in the 1950s, involves a type of reciprocal change with a paradoxical element. Mostly seen in two-movers, the theme follows this pattern of play: a white try threatens mate A and the black defence x allows mate B, but after the key, mate B becomes the threat and the same defence x leads to mate A. Thus the threat-move and the mating response to a particular black move are interchanged between the try and post-key phases. Unlike the standard reciprocal change of mates, which requires two thematic black defences (e.g. the recent Weekly Problem No.357), the le Grand scheme entails one defence only and hence there is just one main variation per phase. On the plus side, the threat-and-mate reversal is more paradoxical, as the problems below will demonstrate.

Octave Chatillon
La Presse 1900
Mate in 2

Our first illustration has a remarkably early publication date – so early, in fact, that it’s likely that the pattern in question was rendered accidentally. Regardless, this miniature shows the theme as cleanly as most modern examples. The try 1.Sd5? threatens 2.Qg8 [A], and Black defends by playing 1…Kg6 [x], which is answered by 2.Qe8 [B]. But 1…Ke6! defeats the try. The key 1.Bb2! threatens 2.Qe8 [B] instead, and 1…Kg6 [x] again defends, but now 2.Qg8 [A] mates. (By-play: 1…Ke6 2.Qd7.) Inherent to the le Grand theme is a double paradox, which in this example can be described thus: (1) 1…Kg6 disables 2.Qg8 in the try play and yet enables 2.Qg8 in the actual play, and (2) 1…Kg6 enables 2.Qe8 in the try play and yet disables 2.Qe8 in the actual play.

Friedrich Chlubna
Probleemblad 1991
8th Hon. Mention
Mate in 2

The second problem generates the reciprocal change with intricate strategic effects. The thematic defence 1…cxd3 has a set mate, 2.Qd4, which isn’t part of the main scheme but it represents a bonus change from the subsequent play. The try 1.Rf3? guards d3 to threaten 2.Sa4 [A]. 1…cxd3 [x] defends by removing the knight’s control of b4, but the black pawn has opened the b4-rook’s line to d4 and also pinned itself, admitting 2.Qe1 [B] (not 2.Qd4 due to the activated h8-bishop). The try, however, is refuted by 1…Ra5! The key 1.Rf4! guards d4 to threaten 2.Qe1 [B]. Since 1…cxd3 [x] here doesn’t self-pin the pawn, it counters the threat, but because the pawn has blocked d3 and also opened the f4-rook’s line to b4, the mate is switched to 2.Sa4 [A]. Black has one other defence, 1…Re5, which deactivates the h8-bishop again and permits 2.Qd4. This variation brings back the set mate for 1…cxd3, effecting a mate transference that further enhances the cohesion of the whole composition.

9 Nov. 2017 – The le Grand theme – Part 2

In this follow-up column on the le Grand theme, we look at some ways by which the idea could be elaborated. Recall that the theme involves a type of a reciprocal change between try and actual play, based on this pattern: a try threatens mate A and the defence x permits mate B, but the key threatens mate B instead and the same defence x allows mate A. In the first example, the scheme is augmented by another thematic try to bring about a three-fold change of mates. The second problem illustrates how the le Grand could be effectively transposed to a three-mover.

Peter Hoffman
Die Schwalbe 1989
3rd Prize
Mate in 2

The black king has a flight-move to e4 and it is the thematic defence. The first try 1.Bf4? guards d6 to threaten 2.Sxf6 [A], and since the try-bishop has also covered e3, 1…Ke4 [x] enables 2.Qc4 [B], but 1…f5! refutes. The second try 1.Be2? controls c4 to threaten 2.Qc4 [B], and now 1…Ke4 [x] permits 2.Qd3 [C], thanks to the extra guard on d3 by the try-bishop; however, Black escapes with 1…Ke6! Finally, the key 1.Bd7! attacks c6 to threaten 2.Qd3 [C], and 1…Ke4 [x] leads to another changed mate, 2.Sxf6 [A]. Instead of the reciprocal pattern found in the standard le Grand, this problem shows an extended version with a circular relationship between the moves: first try? (threat 2.A), 1…x 2.B; second try? (threat 2.B), 1…x 2.C; key! (threat 2.C), 1…x 2.A. This is a cyclic le Grand, impressively achieved in miniature form.

Though nominally a two-move scheme, the le Grand could also occur in three-movers. One method of transferring the idea, exemplified by the problem below, dispenses with the thematic try but shifts the main play to the second and third moves. Thus White has two second-move continuations (corresponding to the try and the key of a two-mover), each followed by a threat [3.A or B] and a variation mate [3.B or A], and these third moves are reversed with respect to the same second-move defence [2…x].

Waldemar Tura
Martin 1995
2nd Prize
Mate in 3

The key 1.Ra4! carries the threat of 2.Bc4+ Kc6 3.Sd8, against which Black has only two defences, 1…Qb4 and 1…Qc3. Either black move means White could push the f2-pawn and threaten a queen mate on e4 or e5, since 2…Qh4+ has been ruled out. Now 1…Qb4 forces 2.f3 with the threat of 3.Qe4 [A], and 2…d3 [x] opens not only a defensive line for the black queen but also an offensive line for the b2-bishop: 3.Qe5 [B]. (2…Se6 3.Qxe6.) Not 2.f4? here because of 2…Qxb5! If 1…Qc3 then 2.f4 threatens 3.Qe5 [B], and the same defence 2…d3 [x] opens both a defensive line for the black queen and an offensive line for the white rook: 3.Qe4 [A]. (2…Sd7, etc. 3.Qe6.) This time, not 2.f3? because of 2…Qd3/Qc2! The double paradox of 2…d3 disabling/enabling 3.Qe4/Qe5 is apparent here, along with the beautifully matched line play.

17 Dec. 2017 – If a pawn could “promote” to a pawn…

Lately I’ve been visiting the forum of Chess.com, and came across a topic that posed an interesting question. Suppose it is legal for a pawn to stay as a pawn upon reaching the eighth rank; are there situations in which such a promotion – or rather, non-promotion – would be the best move? Apparently the question was answered in the affirmative back in the 19th century, when the pawn promotion rule was in dispute. A position cited by Steinitz demonstrates how a pawn promoting to a pawn (P=P) could be the only way to salvage a draw, through stalemate. Although this problem has reasonable economy with thirteen units, that seems improvable and I constructed an eight-unit setting, using only pawns besides the kings.

Peter Wong
Chess.com 2017
White to play and draw
Legal P=P

After 1.e8(P)!, Black cannot release the stalemate. White would lose with 1.e8(Q)? g3 2.Qg6 g2+ 3.Qxg2+ fxg2.

What about a position in which only a P=P move could force a win? This is a much harder task, of course, and at first I was sceptical that it was possible. In such a problem, the only feasible reason that other choices of promoted pieces would fail is that White is induced to use these pieces to stalemate Black. And given that a newly promoted rook, bishop, and knight control completely different squares, at least three different stalemates need to be organised in response. Be that as it may, I couldn’t resist the challenge and eventually came up with the following position.

Peter Wong
Chess.com 2017
White to play and win
Legal P=P

The black queen threatens mates on a8 and f7, severely limiting White’s options. 1.exf8(Q)? or 1.exf8(R)? pins the knight and stalemates Black immediately. 1.exf8(B)? guards g7 and allows Black to deflect the f5-knight with 1…Se7+ 2.Sxe7= (or 2.Bxe7=). 1.exf8(S)? controls h7, which means Black can eliminate the f6-knight with 1…Sxf6+ 2.gxf6=. If White attempts 1.e8(Q)?, Black still draws with 1…Qxf7+ 2.Qxf7 Se7+ 3.Qxe7= or 3.Sxe7=. Only 1.exf8(P)! wins, avoiding all the stalemate traps. Best for Black is 1…Sxf6+ but after 2.gxf6 Kh7, White is still a piece ahead and so wins the ending easily.

I wondered if there were precursors to these problems, or if the tasks could be arranged more economically. The best place to ask such questions is the Mat Plus forum, which attracts an active community of problem composers. The answers I received were striking, and include a three-mover by the great Sam Loyd that is solved by a P=P key! The Draw task was accomplished by a few problemists in miniature, and my Win study above was modified in an amusing way. Here’s a link to check out these compositions: A pawn remaining as a pawn upon promotion.