Clearing Paths to the Targets

Now consider another variation on our theme:

a potential fork is frustrated by a piece lying between the forking square and one of the targets—the king or the loose piece. Again much of our attention will be devoted to the process of noticing such situations; once they are found, standard tools—threats and ex-changes—often can be used to resolve them.

The most important general skill here is the ability to see “jump checks”: moves that would give check if some piece (perhaps an enemy piece, or perhaps one of your own) weren’t in the way. These are important to see generally, and they are especially important if you have found a loose enemy piece. For then you turn all your efforts to looking for a way to attack the loose piece and give check at the same time, and you don’t want to overlook a check just because there is a piece that would need to be gotten out of the way before it can work. The best way to find checks like this is to try just aiming pieces at the enemy king. If pieces of your own are in the way, look for time-consuming threats you can make by moving them. If your opponent’s pieces are in the way, try to force them off their squares with threats or by taking pieces they protect.

Dg148: White to move

Dg148: In this first example, look first for any loose enemy pieces. Here Black’s rook is loose at d7. Can White’s queen attack it and give check at the same time? No, not yet. But if the queen moved to g4 it would be aimed at both king and rook; thus only the Black pawn at g7 prevents a successful fork. So ask whether White can draw that pawn out of the way by taking something it protects. The g7 pawn guards the bishop at f6, which White can take with his rook. So 1. RxB, g7xR; 2.

Qg4+ gets the Black rook and wins a piece.

Dg149: Almost the same. This time it is Black's turn to move, so first look for any loose White pieces and find the rook at a2.

Now ask whether Black’s queen can attack it and give check at the same time.

Dg149: Black to move

No, not yet; but if the queen moved to d5 is would be aimed at both king and rook. Only the White pawn at g2 prevents this from being a successful fork. So ask whether that pawn can be drawn out of the way by capturing something it protects. It protects the knight at h3, which Black can take with his rook. So 1.

. . . RxN; 2. g2xR, Qd5+ wins a piece.

Dg150: White to move

Dg150: Are any Black pieces loose? Yes, the knight at d7. Can White’s queen attack it and deliver check at the same time? No, but Qg4 would aim the queen at both a loose piece and the king; it would be a winning fork but for the pawn at g7. White’s goal therefore is to draw that pawn out of the way. Ask whether the pawn is protecting anything that White can attack, and you are led to 1. Bxh6; now if 1. ...g7xB, then 2. Qg4+ takes the knight, gaining a pawn and wrecking the Black king’s pawn cover.

These first three examples all are basically the same, of course; they involve creating holes in the king’s pawn cover so that the queen can

check the king and attack a loose piece else-where at the same time.

Dg151: Black to move

Dg151: A search for checks for Black turns up Qb1; a search for loose White pieces turns up the bishop on b7. Qb1+ would indeed be a winning queen fork if the pawn on b3 weren’t in the way. So now the position becomes easy: to move a pawn, take something it pro-tects. Black plays RxN; White replies b3xR;

and Black then has Qb1+, taking the bishop next move and netting two pieces for a rook.

Anytime you have long open lines available to your queen, inspect them carefully for op-portunities like this.

Dg152: Black to move

Dg152: It might look for all the world like Black has nothing here; the lines to White’s king appear cluttered and inaccessible. The trick is to notice that White’s rook on a1 is loose, and then that Black’s queen is one move from being able to attack it with Qg7.

(The open long diagonal should be conspicu-ous.) The question is whether the attack on the rook can be paired with a check to create a fork. A line from g7 to White’s king would

need to be opened, so study the obstacles on that line—the little cluster of White bishop and Black pawn, with a White pawn on f5.

This cries out for a pawn capture that clears both blockages out of the way: g6xf5—and now White has to either move the bishop or lose it. If he moves it, Black has Qg7+, win-ning the rook.

At first the g-file in this position looks impas-sible because of the two men that lie on it;

Black’s pawn capture is a very useful maneu-ver, worth a long look, as it creates an unex-pected open line in a hurry.

Notice that this position is structurally similar to the previous one. In each, you start by see-ing that your queen is one move from besee-ing able to attack either the enemy king or a loose enemy piece (half a fork); and you see that the queen also would be aimed at the other half of the fork—whichever of those two pieces (the king or the loose piece) it wouldn’t be attack-ing directly. The hindrance in both positions was that one of the lines the queen needed was blocked; the challenge both times was to get rid of the blockader; the solution in each case was to start with a capture of something the blockader guards, forcing it to evacuate the needed line and leave it open.

Dg153: Black’s queen has a check that must be seen (queen checks always must at least be seen!): Qb4. When you examine a queen check you are looking in part for forking ideas; the question is whether Qb4 attacks anything else.

Dg153: Black to move

Not directly, no, but from b4 the queen is aimed at the knight on h4, which is loose and therefore a target. The problem is the White pawn on f4. Can it be eliminated?

Best would be to take something the f4 pawn protects, but that’s not going to work here; in reply to Nxe5, White has QxN+. So toy with more direct threats to see what they do. Thus g6-g5 is natural to consider, and then you see that it does more than threaten the White pawn. It attacks the knight, too, which has no safe place to flee—an occupational hazard of a knight placed on the edge of the board. So White is about to lose the knight unless he takes the Black pawn that threatens it; yet if he plays f4xg5 he loses the knight anyway to Black’s queen fork Qb4+. (White also can reply to Black’s initial pawn push with Qd4, preparing Qxa4. Or White can play 2. Nxf5, QxN. The material outcome is the same.) There is a matter of move order to consider.

Black could start with Qb4+, forcing Kc1.

Then comes g6-g5, and again White must lose the knight (in effect White’s f-pawn is now pinned). Why not do it this way? Well, you could. But now if White plays 2. Nxf5, Black can’t recapture with his queen, for it is over on b4. Instead Black has to recapture with his e6 pawn, which in turn gives White a passed pawn on e5 that he can push to e6, threatening to promote it eventually and menacing Black’s knight right away. Black can deal with this (one possibility is Qe7, pinning the pawn; another is Qc5, attacking White’s queen), but starting with g6-g5 avoids these complications.

Dg154: White to move

Dg154: Black has a loose rook at d7: a target.

White’s queen can attack it by moving to h3, g4, or f5 (you attack rooks diagonally, and bishops horizontally or vertically), but none of these moves attacks anything else at the same time; the path to the king is blocked by the pawns in front of it. So consider what other resources White can bring to bear—

what forcing moves, and with what results.

Experiment with the knight. It has an easy fork with the check Nf6+; Black has to reply g7xN, not only to avoid losing the rook but to avoid being mated with Qxh7. But then a line to the king has been opened; now Qg4+ at-tacks both king and rook, winning the ex-change.

If you need to move an enemy pawn, whether in front of its king or elsewhere, the most common method is to take something it pro-tects. But another technique to remember, shown here, is to imagine sticking one of your pieces en prise to the pawn and consider whether it makes an interesting threat that your opponent would feel obliged to extin-guish, thus leaving you with an open line on which to play a tactic. Or maybe he will de-cide that he can't afford to extinguish the threat by making a capture because its side effects are too severe (i.e., the queen fork)—

so instead he has to let you push your first threat forward.

Dg155: White to move

Dg155: This is similar to the previous frame.

What Black pieces are loose? The knight at a5 and the rook at e2. It would be hard to fashion a double attack against the knight, but the

rook, isolated deep in White’s territory and near the White queen, is a perfect target. Is there a square White’s queen can reach that would enable it to attack Black’s king and rook at the same time? If the queen were on g4 it would be aimed at both targets. But its path to the king would be blocked by the pawn at g7, and of course the White knight already occupies g4. What White needs is a way for the knight to vacate g4 with a capture or threat that requires Black to respond, and a way to remove the pawn at g7. Nxf6 and Nh6 suggest themselves as ways to achieve both objectives at once. Nxf6 doesn’t quite do it because Black can reply QxN without moving the g7 pawn. But Nh6+ forks queen and king and so requires g7xN in response—after which Qg4+ forks and takes the Black rook.

Dg156: White to move

Dg156: This position illustrates a very useful principle. White has a queen aimed at h7. If the queen had cover from another White piece aimed at the same square, the result would be a mating threat. A classic way to so aim a second piece is by putting a bishop behind the queen, as with 1. Bd3. There is then a stan-dard way for Black to address such a threat:

he moves his g-pawn forward to g6, interrupt-ing the queen’s path (and, in this case, threat-ening it to boot). But the point of the mate threat wasn’t to mate. It was to force this dis-ruption of the pawn cover in front of Black’s king. When pawns step forward as Black’s g-pawn does here, lines to the king often are opened that can then be used for other tactical purposes—such as forks. In this case notice that Black has a loose bishop on d6; after the little sequence just sketched White takes the

bishop with 2. Qf6+, Rg7 (interposing to block the check); 3. QxB.

The pattern here is important to master: lining up pieces against the enemy king’s position so he is forced to move his pawns forward, then exploiting the line he has opened with a fork or other tactic.

Dg157: White to move

Dg157: See the loose rook on c8. See the ex-posed enemy king on h8. See that in one move your own queen nearly can get into po-sition to attack both targets with Qh4. Neither part of the attack works yet; the point is just to recognize this as a common general pattern for a queen fork: the check against the ex-posed king down the side of the board, more or less, and the accompanying diagonal attack against a loose piece on the back rank. The question is whether it can be made effective.

The pawn on h5 blocks the queen’s path on the h-file; and the fork would have to be exe-cuted from g4 anyway in order to reach the loose rook (or else the rook would have to be moved). Well, getting the pawn out of the way is no great challenge; just take what it protects with 1. RxN. After h5xR, White can work with checks and thus is in the driver’s seat: 2. Qh4+, forcing Black’s king to the g-file; then 3. Qxg4+ (the fork) and 4. QxR.

So White gets a pawn, a knight, a rook for a rook—if Black bites by recapturing after White starts with RxN. He probably won’t, which is fine; it leaves you with a piece. But you also have to make sure that he doesn’t have any killer threats of his own to play in-stead, and at this point the position becomes more demanding than at first appears. Look at

any checks Black can play—and not just the first check he can give, but strings of checks.

You need to satisfy yourself that you can es-cape whatever mess he can create. Imagine him replying to RxN with Qa2+. This forces your king to c2; then comes Black’s next check, b4-b3+. This time your king escapes to d1, and Black is out of checks. He can play Qxb2, but since that’s not a check it leaves you with a move to take your rook on g4 out of the danger it still faces from the pawn on h5.

That last point is important. The purpose of looking at Black’s counterthreats is partly to make sure you aren’t leaving yourself open to a mating trap, but it’s also to make sure that Black can’t play any forcing moves (checks, mate threats, or captures) that will force you to move your queen; for remember that while all this action is going on in the near left cor-ner of the board, your rook still has been left en prise to Black’s pawn on h5. The only thing preventing your rook from being taken is the threat of the queen fork discussed in the first paragraph. If Black can find a way to distract your queen, your rook will be a goner because Black will be able to take it without consequence. But he can’t.

There is yet one more possibility you would need to consider: Black can reply to Rxg4 with b4-b3. Again, you are looking for major counterthreats Black could launch; this counts as one of them because once the pawn has moved to b3 it is ready to support mate by the queen on a2. The pawn move also uncovers the threat of QxQ next move. Black might be thinking that this will force White to make the preemptive strike 2. QxQ; then after Black replies RxQ, the queens have been traded and Black is ready to launch a mate threat of his own with Rc8-a8, preparing Ra1#. But this needn’t scare you, for White has another move to play in the middle of that sequence.

If 2. QxQ, RxQ, then White goes with 3. Rc1-h1. This pins the pawn on h5, so now White’s rook at g4 is safe; more to the point, with rooks on both the g and h-files White sud-denly is ready to mate with Rxh5. Indeed, Black cannot escape that result.

This position is worth a good look as a study in anticipating your opponent's counterplay.

The reason the issue needs such close consid-eration here is that White's king is so exposed.

It's next to an open file on which Black has a queen and rook, and its only flight square (c2) is perilously close to being sealed off by Black's b-pawn. This means that White has to be very careful not to end up mated or other-wise burned by operations against his king's position. It can happen at any time—even in the middle of a tactical sequence White initi-ates elsewhere on the board.