# Weekly Problems 2024-B

## 711

Robin Matthews
British Chess Magazine 1950, 1st Prize

Mate in 3

## Solution

After the key 1.Sh5!, the two white knights can carry out four similar threats that are sacrificial deflections: 2.Sf4+ [A] Sxf4 3.Se3 [B], 2.Se3+ [B] Sxe3 3.Sf4 [A], 2.Sxf6+ [C] Sxf6 3.Se7 [D], and 2.Se7+ [D] Sxe7 3.Sxf6 [C]. The AB-BA and CD-DC labels show an incidental reversal pattern of White’s second and third moves. The main theme, however, consists of how Black compels White to play each of the four second-move threats – A, B, C, and D – one by one. 1…c3 creates a flight on c4: 2.Sf4+ [A] Kc4 3.Be6, 2…Sxf4 3.Se3 [B]. 1…Rxc8 creates a flight on e6: 2.Se3+ [B] Ke6 3.Sg7, 2…Sxe3 3.Sf4 [A]. 1…Rxb5 creates a flight on c6: 2.Sxf6+ [C] Kxc6 3.Bd7, 2…Sxf6 3.Se7 [D]. 1…e3 creates a flight on e4: 2.Se7+ [D] Ke4 3.Bf5, 2…Sxe7 3.Sxf6 [C]. The Fleck theme, or separation of the four white threats, is wonderfully combined with star-flights. Skilful construction is illustrated by the white bishop on c8, which apparently serves to guard e6 but ends up also delivering three different mates.

Andy Sag: Post key, all four knight checks are effective threats exploiting the overloaded black knights. Each of the four defensive lines creates a different diagonal flight but in each case one of the knight checks provides for the flight as well as activating one of the original threats.
George Meldrum: The multiple threats are separated by Black’s play which includes giving four king flights.
Jacob Hoover: We have the three-mover analogue of the Fleck theme (which is primarily seen in two-move directmates). In addition – and I found this to be quite the nice geometric touch – after the key the four knights make a rhombus!

## 712

Klaus Förster
Deutsche Schachblätter 1987, 1st Prize

Mate in 2

## Solution

Initially, Black has a number of checks that are provided with set mates: 1…Qf8+ 2.gxf8=S and 1…S8~+ 2.g8=Q. In both cases (except for 1…Sf6+ allowing a dual, 2.g8=Q/S), White must choose the right promoted piece to give a double-check(mate), because the Q + P battery is controlled by the black bishop. The key 1.Sd4! opens a line for the white bishop and threatens 2.Qxg6. Since the key-piece has granted a flight on h6 to the king, most of the set replies to the checking defences no longer work, but given that the knight has also cut off the black bishop, new battery mates – aimed at recovering h6 – are possible. 1…Qf8+ 2.gxf8=Q and 1…S8~+ 2.g8=S. If 1…Sh6+ attacking the queen, then the self-block enables 2.g8=Q as set. The flight-move 1…Kh6 does not counter the threat, 2.Qxg6. Against the two thematic defences, White promotes on the same squares as in the set play, but the choice of promoted pieces is reciprocally changed.

Andy Sag: All black defences involve checks answered by various pawn (sub) promotions. Pity the setting could not be reduced to 12 pieces.
George Meldrum: No way the white knight can make the first move… Wait, what?!

## 713

Josip Varga
Šahovski Glasnik 1988, 2nd Prize

## Solution

A rook mate on the g-file seems likely in view of how the king is restricted. Any black unit blocking f5 would also disturb the mate, so the white king has to be utilised to guard that flight. The king needs four moves to reach e4, meaning the rook has no spare moves and it will deliver mate on g2 in one step. Therefore Black must clear the second rank by promoting all four pawns, without the new pieces attacking the g-file or hindering the white king’s trek. Black’s remaining move is allocated to disabling the c8-bishop’s control of g4. 1.f1=R Kb4 2.b1=R+ Kxc3 3.c1=R+ Kd3 4.d1=R+ Ke4 5.Rd7 Rg2. Four black rook promotions are precisely forced and the task is achieved with good economy of length and a model mate.

Andy Sag: Black pawns promote to rooks in the correct sequence to allow the white king to escape a series of checks and navigate through a minefield to e4.
Jacob Hoover: The order of the promotions is carefully chosen so as not to ruin the plan, as are the promotions themselves – all of them to rooks!
Andrew Buchanan: With so many moves, there are potentially many squares where the black king can be mated on, even though White only has one unit. It surprises me that a sound setting can be found.
George Meldrum: Brilliant and funny too.

## 714

Ivo Tominic
Drago Makuc & Janez Moder Memorial Tourney 1976, 1st Prize

## Solution

If it were Black’s turn in the diagram, only the g1-knight is free to move and this would result in an immediate mate. White cannot maintain the block position, however, and the solution will extend the play to two moves. In two thematic tries and the key, White releases each of the three black pieces pinned on the b-file, only to capture it after its various moves, in order to force the set mate 2…Sg~ by zugzwang. 1.Qb6? unpins the knight: 1…Sa3 2.bxa3, 1…Sxc3+ 2.bxc3, 1…Sxd4 2.cxd4, 1…Sa7 2.Qxa7, but 1…Sc7! refutes since 2.Qxc7 is mate. (1.Qb7? Sc7 2.Qc8, but now 1…Sxd4!) 1.Ra3? unpins the bishop: 1…Bxa3 2.bxa3, 1…Bxc3 2.bxc3, 1…Ba5 2.Rxa5, but 1…Bc5! refutes. The key 1.Bb1! (waiting) unpins the rook: 1…Ra3 2.bxa3 S~, 1…Rxc3 2.bxc3 S~, and 1…Rxb2 2.Bxb2 S~. The Grab theme, in which White captures the same black piece on multiple squares, is presented thrice, and in all three phases the white play is completely dual-free.

Andy Sag: As set, Black can only move the g1-knight giving a battery mate but any white move will either mate or allow one or more additional black moves. The key must provide for the newly mobilised black unit to be captured, pinned or otherwise immobilised (without checking), again leaving only the g1-knight mobile.
Jacob Hoover: A pseudo-one-mover. Moving either knight or the c3-pawn gives Black too much freedom; therefore White must unpin one of the pinned black units. This one was moderately difficult.