Using Mate Threats

Dg164: White to move

Still, we do have some familiar geometry:

Qd5 aims the queen at both the Black king and the rook at a8. Neither side of the attack yet works, but the basic pattern is something to keep in mind. The next step is to experi-ment with checks (White has none) and with captures. The obvious spot for an exchange is f5, where Black has a knight that White at-tacks. How many times is it attacked, and how many times protected? Twice and twice.

So White imagines 1. NxN, BxN; 2. BxB, RxB. Here is the key moment in the exercise:

imagine the board after those exchanges, and re-ask what checks and loose pieces are avail-able. Now Qd5 looks quite different. It’s a check (the only one White then has), and the rook at a8 would be loose and so would be lost to the double attack. This problem is a good illustration of two things: how much a couple of exchanges that don’t seem to do much by themselves can change the board, and the importance of asking simple questions about how the board will look after such ex-changes are complete.

Take the opportunity of this position to think, too, about the coordination of Black’s pieces—and White’s disruption of it. In the diagram Black’s pieces protect each other nicely: his rooks guard each other, and his bishop guards both knights and prevents White from giving check on d5. With a cou-ple of exchanges White ruins this coordina-tion, suddenly leaving Black’s position much

more exposed to brutal tactical shots. It shows how vulnerable a position can be when pieces are protected by other pieces (rather than pawns). A series of captures can force the pieces all over the board and rather abruptly leave one or two of them loose.

2.2.11. Using Mate Threats.

Often the queen can attack a loose piece while at the same time not checking the enemy king but threatening mate. The enemy has to ad-dress the mating threat, so the loose piece is lost just as it would be if the queen had deliv-ered a check. To master this pattern it is im-portant to understand a couple of principles about mating threats and how to spot them. It usually takes two pieces to create a mating threat (or mate itself, of course). The threat of a back rank mate is a prominent exception, but for now just think about a classic set of cases that does follow the pattern: your queen is poised to attack a square next to the enemy king that already is attacked by one of your other pieces. At the same time your queen attacks a loose piece. Your opponent has to defuse the mate threat just as he would a check, giving you a move to take down the target.

Dg165:White to move

Dg165: The diagram illustrates the idea in skeletal form. White has a bishop trained on g7. His queen can threaten mate by jumping to d4 or g4 because either move creates the possibility of Qxg7#. Those mate threats will make a fine anchor for a queen fork of any loose pieces Black leaves within range of d4

or g4. The White X’s in the diagram thus in-dicate squares that White indirectly controls because of the possible fork. (He already con-trols d7 with his queen; but imagine a pawn on d2 and the control again becomes indirect.) If Black leaves a loose piece on any of them (or even a piece defended once but also at-tacked once by another White piece), White may be able to win it by playing one of his two mate threats, Qd4 or Qg4. Black will have to respond to the mate threat by stepping forward one of the pawns in front of his king or in some other way, and then White will win the target. In addition to taking Black pieces left unguarded on those squares, White also can carry out other operations there (ex-changes, or putting his own pieces onto the squares) with more confidence than might appear to the untrained eye.

In real play the details of what White can do here naturally will depend on which piece Black has left on those vulnerable squares, and of course on other pieces on the board that will complicate the picture. The e6 square is defended by a pawn; White wouldn’t be able to use his queen to attack a bishop on a diagonal; etc. Or suppose Black has a loose bishop on b4 and White forks it with Qd4 or Qg4. Black can save his piece by playing the bishop back to f8; this both removes it from danger and adds a defender to g7, thus defus-ing the mate threat. But these are details. The important thing for now is just to realize that in this humble-looking formation White has a strong forking threat waiting to be unleashed, that it isn't related to any check he can give, and that it gives him a measure of control over many squares that appear not to be under attack.

Dg166: Inspect the position for loose pieces and you find the Black knight on c6. White has no safe way to check the king and attack the knight at the same time (Qe8 would do it, of course, but Black’s queen guards the square). So next White looks for a way to attack the knight while threatening mate.

Look for another White piece trained on a square near the king. Here we have a classic example that we will see several times in this

section: White’s bishop is attacking a square next to the Black king (h7).

Dg166: White to move

If White’s queen moves in front of the bishop on the same diagonal―i.e., to g6―then White threatens mate on the next move:

Qh7#. So Black will have to address the threat created by Qg6 by moving his king or bring-ing over his queen. Meanwhile Qg6 also at-tacks the loose knight. So after Black makes one of the replies just described, White plays QxN and takes the knight for free. Think of this as a double attack on the knight and on the h7 square.

Dg167: White to move

Dg167: Here is the same principle in slightly different form. What Black pieces are loose?

The knight at a7 and bishop on d7. White can’t give check and attack either piece at the same time, so he asks whether he might attack one of them while creating a mate threat. He looks for pieces he has trained on squares next to the king and sees that the bishop at a1 is aimed at h8. If White’s queen were to land on h8 the game would be over. So White just needs a square from which his queen can (a)

attack one of Black's loose pieces, and (b) attack the h8 square. Qd4, winning the knight, is the answer.

Dg168: White to move

Dg168: By now this one should be easy. Be-gin with the usual reconnaissance of enemy pieces, looking for any that are unguarded or underdefended; here it turns up the Black knight on e3. White can’t give check and at-tack the knight at the same time, so he looks for the makings of a mate threat: another piece that attacks a square next to the king.

Once more his bishop answers the purpose; it attacks g7. So he looks for ways his queen might attack g7—the mating square—and the loose Black knight. He finds Qd4, which wins the piece.

As these first examples all show, a bishop aimed at squares next to the enemy king can be a valuable resource, as it creates a fertile climate for double attacks with the queen. The mating threats it supports may be simple to defuse (here the simple pawn move f6 puts out the fire for Black), but of course the pur-pose of the exercise never was to deliver mate. It was to take loose enemy material.

Dg169: What White pieces are loose? The rook at e1 (as well as the queen, but focus on the rook for the usual reasons). Black has no safe way to check the White king and attack the rook at the same time, so he looks for a mating threat. Here as before the bishop is the answer: it attacks the b2 square (and pawn) adjacent to the king. Black would mate if his queen were to land on that square. If you fol-lowed the pattern of the previous problems, you might look for a way to put the queen on

the same diagonal as the bishop—for exam-ple, by playing Qd4. But that doesn’t attack the rook, and anyway d4 is protected by White’s queen.

Dg169: Black to move

So Black looks for other squares his queen could reach that would allow it to attack b2.

He finds Qb4, which threatens mate by Qxb2 and also threatens, and wins, the loose rook at e1. The point: there is more than one way for the queen to attack a mating square already being hit by a bishop.

Dg170: White to move

Dg170: What Black pieces are loose? All of them. White has no way to check the Black king and attack any of those pieces at the same time, so he looks for a mating threat; he asks what other pieces he has attacking squares near the king. This time his bishop isn't helpful, but his knight is: it attacks g7. If White’s queen were to land on that square, it would be mate. So White looks to move his queen to a square that would allow it to attack g7 and also attack one of the loose Black pieces. This leads to Qg5, which wins the

rook after Black makes a move to protect against Qxg7#.

Dg171: White to move

Dg171: The only loose Black piece is the bishop at a1. White can’t attack it and give check at the same time, so he looks for mating threats. His knight attacks f7 and h7; the at-tack on f7 is not powerful because Black pro-tects the square with his rook as well as his king, but h7 is only protected by Black’s king.

It follows that if White’s queen attacks h7 it will threaten mate; the h7 square thus can be treated a target in the same way a loose piece or the king itself would be. So the question for White is whether his queen can attack the Black bishop and the h7 square at the same time. It can; Qh1 threatens mate and so wins the bishop. The long backward move of the queen here is counterintuitive, and illustrates the importance of methodically looking at every way the queen can attack the vulnerable points in the enemy position.

Dg172:White to move

Dg172: White’s best move obviously is the free QxN. Or is it? This is a sterling example of the importance of looking beyond a good move to make sure there isn’t a better one. Do

it in the usual way: look for loose enemy pieces, checks, and mate threats. Black’s rook is loose; follow this observation by looking for a line the queen could use to attack it while also being aimed at the king. Qh4 sug-gests itself. The move seems to fail because the h6 pawn blocks your queen’s path to the Black king’s position. But there is more than one way for a fork to “work”; if the move doesn’t give check, it still is enough if it threatens mate. Examine the Black king’s position and you see that White’s rook on the open g-file has the king trapped on the side of the board, and you see as well that the king has no defenders. The conclusion: Qxh6 would be mate. So after White’s 1. Qh4, Black doesn't dare move his rook; he has to let it go. (Then again, no matter what Black does, White can force mate soon enough anyway. If Black plays 1. ...Kh7, for example, then White plays QxR and can't be stopped from playing Qg8#; Black can only delay the move with useless gestures like Ne8 or Qxb3+.)

Dg173: White to move

Dg173: Black just played Bc5, adding a sec-ond attacker against f2 along with his knight;

maybe he meant to threaten a knight fork there. To see why this was a mistake, look at the board from White’s standpoint and ask some standard questions: What mating threat can White make? His bishop attacks f7, a square next to the king and unprotected by any piece other than the king; so White asks whether his queen can add to the pressure against that square and attack any loose Black pieces at the same time. The answers are yes and yes: if White plays Qd5, he now has a mating threat; and he also attacks the loose

Black knight at e4. The knight can jump out of the way and help guard f7 with Ng5, but it's no escape. White already has g5 under attack twice.

So after 1. Qd5 Black is obliged to lose mate-rial. He can play the check Bxf2+, so that his bishop takes a pawn with it on the way down;

but then White calmly plays Ke2, and now two of Black's pieces are under attack—his e4 knight by White’s queen, and his bishop by White’s king. He will lose the knight next move.

Lesson: leaving loose pieces around is dan-gerous business. Before putting his bishop on c5, Black should have noticed (a) that he al-ready had a loose piece in the middle of the board, which always is cause for concern; and (b) that White had a bishop attacking f7, which is cause for additional concern since it sets up a mating threat if White can aim his queen at the square as well. Black would have been better off making a move to address one of those threats. Best is d7-d6, since then after 1. Qd5, Be6; 2. QxN, d6-d5 Black wins back his piece with a pawn fork. (We will look at pawn forks more closely in the later chapter dedicated to them.)

Dg174: White to move

Dg174: Let’s continue to look at the same idea from a defensive standpoint. Here White sees that Black’s pawn on e5 is defended once (by the pawn on d6) and attacked twice (by the pawn on f4 and the knight on f3). So he is tempted to play 1. f4xe5; then if 1. …d6xe5, 2. Nxe5. But please don’t play an exchange like this until you have imagined what the board would look like afterwards—including

what lines would then be open, and with what tactical opportunities then available to you or your opponent. One warning sign is that at the end of the sequence White’s knight on e5, while not attacked, would be loose. Another is that Black’s bishop already attacks f2, adja-cent to White’s king. Nothing except the king protects that square (a common state of affairs in the opening; this is why f2 and f7 often are considered defensive weak spots early in a game); so if Black’s queen were able to attack f2 as well, White suddenly would be con-fronted with a mating threat. The threat could be averted with various moves, but they would take time, and meanwhile Black would be able to take any loose piece his queen also attacked. None of this looks like an immedi-ate worry in the position diagrammed here, but after the exchange of pawns and the re-capture Nxe5 by White, the stage would be set for Qd4, threatening mate at f2 and attack-ing, and winnattack-ing, the then-loose knight on e5.

Dg175: Black to move

Dg175: Here's yet another example of how the prospect of queen forks can figure into defensive thinking. The two sides are fighting for control of the center and especially of the e4 square. Black sees that the White pawn there is protected twice but that he attacks it three times. In his mind’s eye he plays 1.

…Nxe4, 2. BxN, RxB; 3. RxR, QxR. But before executing this sequence he must ask the sorts of questions we have been discuss-ing. First, would this liquidation of the posi-tion leave any open lines at the end that would allow the enemy queen to attack the Black king? Here Qg5 would be available to White, and from there the queen would join the f5 knight in attacking g7—threatening mate.

Indeed, that move already is available. What prevents it from working is the absence of a second target: the queen would be aimed at the rook on d8, but its path would be blocked and the rook would be guarded. But after the exchanges Black imagines on e5, these obsta-cles would be gone. Indeed, the resulting po-sition would be one you saw about five frames ago: it leaves a fork for White. So the sequence Black imagines must not be played;

after it is complete it results in 4. Qg5, Kf8; 5.

QxR+, Qe8; 6. QxN.

This example shows how a few precautionary questions, asked as a matter of course before entering into a series of exchanges, can save a lot of trouble at the end. You carefully imag-ine how the board would look after the series, including any new open lines and loose mate? If this seems like a demanding position, note again that the mate threat Qg5 is avail-able to White from the beginning. Both sides should be conscious of this. It means that if White’s queen were able to attack anything loose from g5 he would have a working fork, so any sequences Black attempts have to be inspected to make sure they don’t produce that outcome. The moral: if your opponent is a move away from being able to create a mate threat, no matter how ineffectual, keep a care-ful eye on it as the potential basis of a fork.

Dg176: White to move

Dg176: Where is the idea this time? You have a bishop trained on g7. One important effect

of such a resource is that you can create a mate threat by adding an attack by the queen against the same square, as with Qg3; so the key question is whether you can make another threat with that move at the same time. You see that from g3 your queen would be aimed at the rook on b8. The position thus has the makings of a classic queen fork, but there are a few problems in the way of its execution.

The rook is guarded by the knight on d7; the queen's path to the rook would be blocked by White's own rook on f4; and the forking square (g3) is guarded by the knight on e4.

Yet none of these difficulties need detain you for long. 1. BxNd7, RxB is a simple exchange that leaves the Black rook loose; 2. RxN, QxR loosens the forking square and opens the

Yet none of these difficulties need detain you for long. 1. BxNd7, RxB is a simple exchange that leaves the Black rook loose; 2. RxN, QxR loosens the forking square and opens the