Clearing Paths

In the following positions there is a rook fork waiting to happen: two enemy pieces on the same rank or file, one of them loose, or one of them the king, or both. But there are pieces between them, or between the rook and the forking square, that have to be gotten out of the way for the double attack to work. Again it is important to recognize the basic visual patterns involved—enemy pieces on the same rank or file, suggestive of a fork—without being thrown off by obstructing pieces that you might be able to remove.

Look for visual patterns on the diagram.

Dg269: We see a familiar layout of Black pie-ces, with the king and a loose knight — prime targets for a fork—on the seventh rank.

Dg269: White to move

If White could get a rook between them, the knight would be his. The Black pawn at e6 is the only thing in the way. The natural method for getting a pawn out of the way is to take something it protects. Here it protects the pawn on d5, so White takes it with Bxd5. If Black replies e6xB, now Re7+ forks king and knight. The net gain is a pawn.

Dg270: White to move

Dg270: White has no checks that are immedi-ately productive (though Ne7+ is not bad), so he looks for any Black pieces that might be loose. There is one: the bishop on h6. He has no direct way to attack it, but since a loose enemy piece is a big opportunity White con-siders whether he might build a double attack against it. Look for a visual pattern: the bishop is on the same rank as the Black queen. If the pieces between them could be cleared out of the way, White would have a fork with Rc6; the rook would be protected from QxR by the pawn on d5. Of the two men in the way, White can control its own—the knight at c6. Where can it move, and with what results? The only capture it can make is NxN. Black would reply d6xN; the pawn gets pulled off the sixth rank. Now the way is clear for Rc6, forking bishop and queen and thus winning a piece. The initial capturing se-quence here illustrates a pattern of general interest: when two pieces need to be cleared off of a path, sometimes moving one of them also can force away the other.

Dg271: Look for a pattern; look for enemy pieces arranged on the same line. Black’s king, rook, and bishop are spread along the back rank. If the rook were out of the way there would be a classic setup for a double

attack with White’s rook: a king and loose bishop on the same rank with nothing be-tween them. Can the Black rook be attacked?

Dg271: White to move

No. Can White attack something the rook protects? What does it protect? The knight on e4. So White takes the knight with NxN, Black responds with RxN, and now with the Black rook out of the way White plays Rd8+

and wins the bishop. That would be one way to see the position; another would be to begin by experimenting with captures. White sees that he can play NxN. Automatically he imag-ines it and considers what it would do to the board. It would cause Black to play RxN.

Then what would be possible—especially what checks? Answer: the fork Rd8+.

When the queens are faced off against each other like this, exchanging them is an option both sides have to consider at every turn. A capture by either player will require an imme-diate recapture, which may open lines, leave loose pieces elsewhere, etc.

Dg272: White to move

Dg272: Here White imagines QxQ and Black’s compulsory recapture NxQ. This

simple sequence leaves behind loose Black pieces on c5 and f5 (whereas there were no loose Black pieces before), and a clear path for White’s rook from e1 to e5 (whereas there were two pieces in its way at the outset). Now the rook fork Re5 wins a piece.

This position is a good illustration of how a single exchange can radically alter the tactical opportunities on the board. The solution is easy enough to spot if you understand the significance of loose pieces—and probably impossible if you don't.

Dg273: Black to move

Dg273: Start by seeing that the tension in the position is focused on c4: Black has two pieces attacking the bishop there; White has two pieces defending it. This means Black can’t win anything immediately with captures on that square, but if you stop there you're thinking about the position the wrong way.

The important question when you have a chance to force a series of exchanges is how the board would look afterwards — what checks you then would have, and whether any of them would be (or could be made into) forks or other tactical devices.

Okay, so imagine liquidating the pieces trained on c4. Black plays BxB, and White replies RxB; Black plays RxR, and White replies RxR. The two sides have traded bish-ops and rooks. More importantly, one of the rooks in White’s battery is off the board and the other ends up on c4, leaving White’s back rank weak (bereft of defenders). The natural thought for Black, then, is to drop one of his own rooks there with check: Rd1+. This forces White’s king to f2—on the same file as

the b2 bishop, which would have been left loose by the exchanges that started the se-quence. The rook fork Rd2+ then wins the bishop next move.

The prospect of a rook fork is nowhere in sight at the outset of this position. You would see it only by patiently imagining the exhaus-tion of exchanges on c4, then your next check, then the resulting pattern with the king and loose bishop on the same line. If the latter position were set in front of you its solution would be clear. It is worth studying this posi-tion until its soluposi-tion is equally clear because you are able to visualize the consequences of those initial moves. Notice that it involves several of our major themes in constructing forks: creating a loose target, loosening the forking square, and moving the enemy king onto a square where it can be forked.

Dg274: Black to move

Dg274: You might start here by looking for visual patterns for Black to pursue. The key thing to notice is the spread of pieces on the second rank and especially the White bishops there. Of course there are pieces between them, but if the queens were removed a dou-ble attack would be possidou-ble; as usual the sec-ond rank is a great place for a fork because it can’t be defended by pawns. The bishops there are especially nice targets because unlike the White queen that also is there, they wouldn’t be able to strike back at a rook that jumped between them.

So Black goes to work to get rid of the ob-structions, starting with the obstructing piece that he can control: his own queen. Experi-ment with exchanges. If Black plays QxQ,

White plays RxQ. Now only the White rook would prevent a fork of the two bishops. Can it be taken? No. Can something it protects be taken? No. But can the rook be threatened and perhaps driven away? Yes, with Bb4.

White moves the rook so as to avoid BxR;

and now Black plays Rc2, attacking both of the now-loose bishops and winning one of them.