Weekly Problems 2020-B
OzProblems.com 4 Jul. 2020
Mate in 2
The black king has a flight-move that initially produces a double pin-mate: 1…Kxe4 2.Qh4. Another set variation exploits the masked Q + S battery: 1…Bf4/Bg3 2.Sxf5. Both of these lines are abandoned by the key, 1.Qa8!, which threatens 2.Qxd5. Now 1…Kxe4 results in an even better triple pin-mate, 2.Rxc4. Three other captures of the e4-pawn, involving self-blocks and unguards, are met differently: 1…Qxe4 2.Qa1, 1…Sxe4 2.Se6, and 1…dxe4 2.Rxc4. Lastly, the f5-knight prompts two distinct mates on e3: 1…Sxe7 2.e3 and 1…Se3 fxe3. Multiple defences on the same square, and the two queens operate from all four corners of the board. (If the f7-rook is placed on f4 instead, that brings about another thematic variation, 1…Rxe4 2.Sxf5, but the important set mate for the flight would be lost.)
Karel Hursky is an Australian problemist who resides in Sydney. He is an active tournament player and composes only occasionally, but has a number of high-quality selfmates and helpmates under his belt.
Andy Sag: The two exd captures create vertical flights. That and the clear eighth rank and a-file make the key rather obvious. However, the changed mate with the addition of a third pin is quite cute.
Nigel Nettheim: Not hard to solve (…dxe4 is unprovided) but the highlight is the play, especially the four captures on e4 and the white queen’s baseball-like run to second base.
George Meldrum: I love this problem. The queen abandons the set play after the king flight to set up an even more spectacular response to the king move, truly the pinnacle.
Ian Shanahan: The set double pin-mate after the flight-capture is spectacularly changed to a different, triple pin-mate! Then we see three self-blocks on the flight-square and two more pawn mates thrown in for good measure. It’s a pity that 2.Rxc4 is repeated. Anyway, a grandiose two-mover in traditional Good-Companions style.
White’s plan is to add a second attack on f8 so that Rxf8+ would force Black to recapture with the h7-knight and mate by discovery on the h-file. Hence White seeks to double the rooks on the eighth rank, and out of four candidate moves by the c8-rook, only 1.Rd8! works, for a reason not apparent until eight moves later. Black defends by queening various pawns and checking on c1, in an effort to draw one of the rooks away from its threatening position. 1…d1=Q 2.Rcc8 Qc1+ 3.Rxc1 fxg1=Q 4.Rcc8 Qc1+ 5.Rxc1 g1=Q 6.Rcc8 Qc1+ 7.Rxc1 g2 8.Rcc8. Now 8…g1=Q? is too slow against 9.Rxf8+; instead, Black guards the f8-knight directly with the newly mobilised bishop, 8…Bd6. The farsighted key, placing the rook on the d-file, has provided for this defence: 9.Rxd6. Still, the bishop sacrifice has gained a tempo for Black and makes 9…g1=Q viable, to further delay White’s goal. After 10.Rdd8 Qc1+ 11.Rxc1, however, there’s no further stopping 12.Rcc8 and 13.Rxf8+ Sxf8. An impressive selfmate sequence that delivers four black queen promotions, shown with great precision.
Composer: The concept isn't entirely new (see my selfmate in 15 on superproblem.ru) but it has original elements to it, such as the key and the unique order of Black’s play. (The b4-pawn serves two purposes – it prevents 2…Qd2+ 3.e3 Qb4 and gives Black enough moves such that mopping up the black pawns fails in time.)
Andy Sag: White can play Rxf8+ once both rooks are on eighth rank. Black keeps delaying this by checking on c1 or guarding f8 until eventually running out of pieces.
Jacob Hoover: 1.Ra2? is a fourth try. This is the longest selfmate I have attempted to solve by a longshot.
Nigel Nettheim: An imaginative scheme, with c1 visited eight times. White’s first move anticipates black’s eighth.
George Meldrum: With the idea of placing both white rooks on the eighth rank the journey of solving this problem begins. It is much later in the journey that White’s first move is discovered when the bishop move needs to be dealt with in this crazy problem – crazy good.
Olympic Tourney, Thessaloniki 1984-88
Mate in 2
Three set variations utilise the white queen to mate on the e-file: 1…fxe6 2.Qxe6, 1…fxe5 2.Qxe5, and 1…Sg4 2.Qxe4. The curious half-battery arrangement on the fifth rank means that shifting the queen will create the threat of 2.exf6. In three thematic tries by the piece, it manages to preserve two of the set mates on the e-file but fails to account for the third defence: 1.Qd4? fxe6!, 1.Qc4? fxe5!, and 1.Qd6? Sg4! Such a scheme, in which three black moves rotate their functions as normal defences and foiling responses against three tries, is called cyclic refutation. The key-move naturally caters for all three defences, but 1.Qd2! does that by setting up new mates for them: 1…fxe6 2.Bg6, 1…fxe5 2.Qg5, and 1…Sg4 2.Qf4.
Andy Sag: The c6-pawn indicates a queen key but all three set mates must be abandoned.
Andrew Buchanan: Various changed mates, etc: good stuff.
Nigel Nettheim: The “she stoops to conquer” theme, though she was sent on her way by the c6-pawn.
Jacob Hoover: An excellent two-mover.
Ian Shanahan: There are three tries where two of the set-mates work, but the third refutes the try (cyclic refutation). Only one destination works, whereby all three defences lead to changed mates. An elegant and clever problem!
Robert Burger & Robin Matthews
British Chess Magazine 1988, 1st Prize
Mate in 3
White cannot open the B + P and R + P batteries aimed at the black king solely because the pawns involved are blocked by another pair of white pawns. If White begins with a king move, that will threaten 2.c8=S and 3.Sb6 or 3.c7, but 1.Kd7? is too weak against 1…Sxf6+ while 1.Kb8? fails to 1…Sxc7! followed by 2…Sa6+. The key 1.Kd8! avoids these spoiling checks, and Black’s only defences are to use the knight to capture the pawns that are obstructing the battery play. After 1…Sxc7, White continues with 2.e8=S to threaten 3.Sxc7, and a random knight defence, 2…S~, allows 3.c7 – White exploits the annihilation of the c7-pawn to fire the B + P battery. The correction move 2…Se6+ activates the R + P battery instead, 3.fxe6. The other thematic defence, 1…Sxf6 (which deters the 2.c8=S threat with 2…Sxe4!), induces a different promotion by the same pawn, 2.e8=Q. Now the threat of 3.Qxf7 is answered by any knight move (as it opens the rank for the black rook), and 2…S~ facilitates 3.f6 – effecting a similar annihilation of the f6-pawn to free the R + P battery. The knight has two corrections: 2…Sd7 triggers the B + P battery, 3.cxd7, and 2…Sxe4 permits 3.Qxe4. Wonderful reciprocal battery play with two pairs of matching mates along diagonal and orthogonal lines, all set off by a single defender.
Andy Sag: Clever play with sub-promotions and battery mates.
Nigel Nettheim: The dual third-move threats are separated in 1…Rh3 2.c8=S Rxd3 3.c7 and 1..Rh1 2.c8=S Rc1 3.Sb6. The different promotions on e8 are attractive too. Not hard to solve because the white bishop was likely to take part.
Jacob Hoover: In the first line the battery on the fifth rank fires in response to the random knight move while a correction forces the firing of the battery on the long diagonal, whereas in the second line the reverse happens.
Szachy 1970, 1st-2nd Prize =
Mate in 2
Two set mates by the e8-knight close white lines of guard but are playable after black self-blocks: 1…Se5 2.Sd6 and 1…Sg5 2.Sg7. In two thematic tries, White threatens each of these knight mates, but Black refutes them by opening lines for the h2-bishop and g1-rook: 1.Qc3? (2.Sd6) but 1…f3! and 1.Qh4? (2.Sg7) Se5 2.Sd6, but 1…Sf2! The Novotny key 1.Qg3! cuts off the same two black line-pieces to threaten 2.Rxf4 and 2.Bxg4. These threats are separated through captures of the key-piece: 1…Rxg3 2.Rxf4 and 1…Bxg3 2.Bxg4. The main variations (where both threats are stopped) bring back the knight mates seen in the virtual play, but in a paradoxical way. The defence 1…f3, which disables the threat of 2.Sd6 after the 1.Qc3? try, now opens a white queen line and enables 2.Sd6. Likewise, 1…Sf2, which disables the threat of 2.Sg7 after the 1.Qh4? try, now opens another queen line and enables 2.Sg7. Such a pattern of recurring moves with ironically changed functions is called the Dombrovskis theme.
Paz Einat: A crisp Dombrovskis. The Novotny is perfectly used to close the thematic lines that feature in the refutations of the two tries.
Nigel Nettheim: Quite intricate. The h6-pawn is justified by turning 1.Qh4? into a try, matching the 1.Qc3? try.
Jacob Hoover: In the set play we have a Grimshaw pair (1…Rg3 2.Rxf4, 1…Bg3 2.Bxg4) and a pair of self-blocks (1…Sg5 2.Sg7, 1…Se5 2.Sd6). The try 1.Ba4? (threat: 2.Bd7) preserves the set self-blocks and knight mates completely but dies to 1…Sf8! The key is a Novotny interference. The two threats are separated and in addition, the key transfers the other two set mates to different defenses (1…Sf2, 1…f3), each one of which opens a guard of one of the squares that were involved in the set self-blocks.
Ian Shanahan: Wow! What a rich melange of thematic ideas! Firstly, we observe mate transference between set and actual play, self-blocks plus white interference in the first half of the set play, and the Grimshaw theme in its second half. The key itself, with its double interference, flaunts the Novotny theme. The mates threatened by the tries follow the very defences which refute the respective tries – a paradox known as the Dombrovskis theme. The only tiny blemish I can see is that in the second try (1.Qc3?), there is no variation leading to 2.Sg7 – as a counterpoise to the first try's 1.Qh4? Se5 2.Sd6. The composer is to be congratulated! This has to be one of the most beautiful two-movers that I've encountered in ages.