Other Mating Threats.

The mating threats considered so far all have involved a attack by the queen on a square already attacked by another piece—typically a bishop. That is the most common sort of mat- ing threat to use as part of a queen fork, but there are others as well; here we'll consider a few examples. Many of them involve an ini- tial move to set up the fork (a check, capture, or threat) followed by a double attack that includes a mating threat. Like the studies to- ward the end of the chapter on knight forks, they require a willingness to play with the consequences of various checks and captures, always asking about the next check that would be available and looking for familiar patterns to emerge.

Dg183: White to move

Dg183: Start with the position. Scan for loose Black material and you find the rook at c5 (and the queen; but focus on the rook). White has no way to attack it and give check at the same time, but do not give up; study the Black king’s position carefully. What are the constraints on its movement, and what are its resulting vulnerabilities? It is stuck on the back rank with no defenders there. If White’s queen or rook were to land on the back rank, it would be mate. So the back rank itself be- comes a target in just the way that a loose piece would be; White’s goal is to attack the Black rook and the back rank at the same time. What move threatens both? Qb4, win- ning the rook after Black fends off the threat of Qb8+ (and QxQ# after Black interposes his queen) with a move like h7-h6.

Dg184: White to move

Dg184: White has no promising checks or mate threats, and only Black’s rooks (and a pawn) are loose. Experiment with captures to see how they and the responses they force would change the board. White has an inter- esting one available in Nxe5; Black would reply NxN. Evacuating the knight from f3 would open the familiar line for the queen to reach h5, and from there to check the Black king. Qh5 also would attack the Black knight that would then be at e5.

At first this looks like a perfect double attack, but actually it isn’t; for consider as well what move you then would make if you were in Black’s shoes. As we recently saw, a common hazard of making a knight the object of a double attack is that it can jump out of harm’s way and block the check at the same time. That would happen here: Black would play

his attacked knight from e5 to g6. But just keep pushing, always asking what lines would then be open and what checks then would be possible. With White’s queen on h5, Black’s knight over on g6 instead of on c6, and the e5 pawn off the board, White has another, more effective attack: recall that the a8 rook is loose; and now White has a fresh mating threat to create with Qd5, adding to the bishop’s existing attack on f7 (remember that a bishop attacking that square early in the game always is a promising setup for a double attack). After Black fends off the mating threat, White takes the rook with his queen. If you look at the original position again you might be able to see the outlines of a fork waiting to happen: if White could get his queen onto d5 and clear the c6 knight out of the way, he would win the rook on a8 by cre- ating a mate threat against f7. But making those adjustments takes a couple of moves and requires the queen to take a circuitous route.

Dg185: Black to move

Dg185: White has a loose rook on g5. Black’s queen has no checks, and the mating threat Qd5 doesn’t work because White's rook guards the square (as well as g2). But there are other ways one can threaten mate. Study the constraints on White’s king. It is blocked by its own pawns. Qe7 thus attacks the loose rook and threatens mate on the back rank with Qe1. But this is another of those cases where you have to ask whether White might save the target and defuse the mate threat at the same time. The rook can’t do this by moving, but White does have the simple resource of h2- h4, guarding the rook and giving the king an

escape square. Yet as we saw most recently in the previous problem, this sort of possibility should not discourage you. Ask what check would then be possible, and with what conse- quences. Black could play Qe1+, which would force Kh2. And then what check could Black offer? Qxh4—checking the king and again attacking the rook, and this time win- ning it. It's all about persistence with checks.

Dg186: Black to move

Dg186: The knight on c4 is the important target here—important because it lies loose on the same rank as Black’s queen. Black wonders if he can find a way to attack the knight and White’s king at the same time. The idea would be to get the pawns out of the way between the queen and knight, and to use the g-pawn to support a mating threat by the queen that keeps White busy. Clearing away the White pawn at e4 is the first order of business. Black attacks it with nothing, and anyway capturing would not help because that still would leave the fourth rank cluttered. No, the other standard route is a better way to re- move the pawn: capture something it protects, here the d5 knight. Black plays BxN, White replies e4xB, and now the c4 knight is more vulnerable. Next Black needs to move the g4 pawn out of the way and also create a threat with it. The question suggests its own answer: g4-g3 gets the pawn off the fourth rank and also attacks a weak square adjacent to White’s king, creating a threat of mate with Qxh2+ followed by Qh1#. White easily parries all this with h2xg3, but this costs him a move, after which QxN follows.

After Black’s BxN, White also has the option of g2-g3, attacking Black’s queen. At first this

looks good; if the queen can be driven away, maybe White will be able to take the Black bishop without the fork Black has planned as a follow-up. But it turns out not to be advis- able; for Black has the reply BxNc4, captur- ing another piece, unmasking an attack by his rook on White’s queen, and aiming his bishop at the White rook on e2. White has to respond by playing his rook to d2, giving it protection and also protecting the queen on d1, giving White a chance to move his queen out of dan- ger with a gain of two pieces. Still, the idea of White's counterthreat (g2-g3) is valuable to see, as is the discovered attack against the White queen that makes Black's riposte (BxNc4) so powerful. We will study discover- ies in more detail later.

Dg187: White to move

Dg187: What Black pieces are loose? Just the rook at c6, so White looks for ways to attack it while giving check or threatening mate. Qe4 seems awfully close to working; it at- tacks the rook and, along with White’s knight, threatens h7 for a second time. The hitch is that Black’s queen also protects h7, and White has no way to drive the queen off. Once White sees that only the Black queen stops the winning fork, he focuses on how he might get rid of it—perhaps by harrying it with his pawns. White starts his kingside pawns forward with a threat against Black's knight: h2-h3. Where would the knight go? It turns out to have only one safe square: h6. Ah! The knight then would block the Black queen’s route to h7. Suddenly there is no need to drive off the queen after all; now White's Qe4 would create a serious mating threat be- cause Black’s queen wouldn't be able to help, and the rook at c6 remains loose. So: 1. h2-

h3, Nh6; 2. Qe4 wins the rook. (Black would be better off just forfeiting the knight.) The hardest part about this one is seeing that Black's knight would have to go to h6. Re- member that a threatened knight often has limited options, and that when it is forced to a new square there may be interesting side ef- fects.