More-movers

Longer directmate problems, in which White forces mate in four or more moves, are grouped under the term more-movers. The length of play in such compositions allows themes of greater depth to be realised, such as those involving elaborate manoeuvres. Nevertheless, long directmates are not necessarily more difficult to solve than two- and three-movers. Often White’s choices are limited to making short mating threats, to keep the black force under control. Also, lengthier problems tend to possess fewer variations – one full-length variation is typical in very long more-movers – hence they don’t become unduly complex.

In the classic 19, White apparently needs only four moves to mate, e.g. 1.Bb2 2.Ba3 3.Bf8 and 4.Bg7 mate. The black bishop, confined to white squares, cannot attack any of White’s pieces and seems helpless against this threat. However, Black has a surprising resource: 1.Bb2? Bh1! 2.Ba3 g2 3.Bf8 results in stalemate. Such a self-immobilisation manoeuvre by Black to bring about stalemate is called a Kling combination. White’s key, then, must take this defence into account, 1.Be5! Bh1 2.Bxg3 B-any 3.Bd6 B-any 4.Bf8 B-any 5.Bg7.

Problem 20 depicts a duel between a white and a black rook, when the two pieces repeatedly act against each other in a series of variations. Black's rook on g8 is preventing Sxg3 mate, but if White plays 1.Rxg8?, stalemate results. Instead White seeks to mate on d1 with the rook. Each attempt by the piece to reach the d-file, however, is intercepted by its black counterpart, 1.Rh7? Rg7!, 1.Rh6? Rg6!, 1.Rh5? Rg5!, and 1.Rh4? Rg4!. To get past the rook defences, White plays 1.Rh3! and waits for the black piece to commit itself, e.g. 1…Rg7, after which White makes further use of zugzwang: 2.Rh7 Rg8 (or to g6, etc., not 2…Rxh7? 3.Sxg3) 3.Rd7 and 4.Rd1 (3…Rd8 4.Sxg3). The other lines are similar in requiring the white rook to reprise this “ambush” tactic, 1…Rg6 2.Rh6 Rg~ 3.Rd6, 1…Rg5 2.Rh5 Rg~ 3.Rd5, and 1…Rg4 2.Rh4 Rg~ 3.Rd4.

White has two significant tries in Problem 21 that threaten immediate mates. 1.Sf4? intending 2.Sd3 is refuted by 1…dxc5!, and 1.Re3? intending 2.Rxe2 is stopped by 1…exf5!; in both cases Black’s pawn capture opens a rook’s defensive line. The actual play sees White disabling these defences in a striking way. 1.Rg3! is the fine key, which unpins the black queen but threatens 2.Rg1 mate. The first main variation starts with a cross-check, 1…Qxc5+ 2.Rc3+ Qf2, and now that the c5-pawn has vanished, White can go ahead with 3.Sf4 and 4.Sd3, as the …dxc5 defence isn’t available anymore. The second main variation matches the first closely, 1…Qxf5+ 2.Rd3+ Qf2, and without the option of …exf5, Black cannot stop 3.Re3 and 4.Rxe2. There is also by-play, 1…h2 2.Rg2 (3.Bxf2) Qg3/Qxh4 3.Rxe2, or 2…h1=S 3.Rg1.

An oft-seen device in more-movers is the decoy, where White manipulates a black piece into a less favourable position. Problem 22 illustrates an elaboration of the decoy idea known as the Roman theme. In this position, White naturally aims to mate on the h-file, and the thematic try 1.Rg5? threatens 2.Rh5+. Black defeats this with 1…Be8!, since 2.Rg4 (3.Rh4) can be met by 2…Sg6. The key 1.Rg7! (2.Rh7+) provokes 1…Bf5, decoying the bishop. Now the try-move 2.Rg5 becomes viable because Black no longer has the …Be8 defence. Instead Black must play 2…Bg6, which obstructs a square needed by the knight. White continues with 3.Rg4, as 3…Sg6 is unavailable, forcing 3…Bf5 4.Rh4+ Bh3 5.Rxh3. The Roman theme featured here involves the following strategy. White has a plan (Rg5-h5+) that is refuted by a particular defence (…Be8). White decoys the defending black piece so that its successful defence has to be replaced by an inferior one (…Bg6), which entails a weakness (obstructing …Sg6). This weakness enables White to activate the initial plan (Rg5-h5+).

The previous work, in showing the Roman theme, exemplifies the logical school of three- and more-movers. A logical problem is so named because solving it entails reasoning out a series of plans and their right order of execution. What occurs is that White wants to play certain moves that would lead to mate – these moves constitute the mainplan – but Black defends adequately. So White first carries out a foreplan, with the sole purpose of neutralising that black defence. Once that goal has been accomplished, White proceeds with the unhindered mainplan. The next example provides a more intricate demonstration of this type of more-mover.

White’s mainplan in Problem 23 is to play 1.Bd2 and 2.Ba5 mate, and if 1…c4 2.Be3 mate. But Black refutes this by decoying the white bishop: 1…e1=Q! 2.Bxe1 c4 and now 3.Bf2+ simply fails to 3…Rxf2. White therefore executes a foreplan whose aim is purely to foil that refutation. The plan commences with 1.Kc8! (threat: 2.b8=Q), which compels 1…Bh3+ (because neither 1…Kxa7? nor 1…Bxc6? deals with 2.b8=Q+). White then decoys the black bishop – amusingly in the same way that the white bishop was decoyed in the try – with 2.g4 (3.b8=Q) Bxg4+ 3.Kb8 (4.Ka8 and 5.b8=Q), and Black has to play 3…Bf3, to answer 4.Ka8? with the pinning 4…Bxc6!. Now the objective of cutting off the rook on f7 has been achieved, so White is able to launch the mainplan, 4.Bd2 e1=Q 5.Bxe1 c4 6.Bf2.

Have a go at solving the four-mover 24, which combines two thematic ideas.