Thursday, April 23, 2015

Calculating Forcing Moves: Defensive Idea 5 - Counterattack to DRAW (material)

In this series of posts we are looking at “counterattacking to DRAW”, which is using Equal or Greater Threats to force three types of drawn positions:

Draw by stalemate;
Material draw (equal material, fortresses, etc); and,
Draw by repetition.

In the last post we looked at a position where there was a clear checkmate threat on the board, and we created an EGT that allowed us to force stalemate.   In this post we’ll use an EGT to force a trade of material so that the resulting position is a material/technical draw.

White just played 1. Rb8.  Black to move.

qR6/p7/3Q1nk1/5p2/r1P1pP2/4P1K1/P7/8 b - - 0 1

Let's evaluate the position, and then find and prioritize all of white's threats.

Evaluation:  Black is up two points (one white pawn vs black knight), but white’s passed pawn could offer white some opportunities and his pieces are more active than their black counterparts.

White’s advantage in activity is temporary and can easily slip away.  Black’s material advantage is significant and more durable.  This material/activity imbalance is similar to our earlier “counterattack to WIN” position.  There we were black and, like in this position, had a two point material advantage (a white bishop vs a black rook).  We won by using an EGT to force equal trades that lead to a winning position.  The same basic plan holds true in this position.  If black can force equal trades of material he will have a winning material advantage.

Threats:  White’s threat is to capture black’s queen, and if the black queen leaves the back rank white could have some play against the black king and pinned knight.  So 2. Rxa8 is the priority threat for calculations.

Let's look at the five defensive ideas to see what candidate moves we can find for black to reply to the threat.

Idea 1 – do something to the attacking piece (the b8 rook).  We can capture it (1…Qxb8), we cannot pin it to anything of greater value, and we cannot deflect it.  So Idea 1 has generated one specific candidate move.

Idea 2 – block the attacking piece (the b8 rook).  Not possible because there are no squares between the rook and queen. I call this an “in your face” attack.

Idea 3 – move the piece being attacked (the black queen).  The queen can move to three other squares (b7, c6, and d5), but they all appear unsafe and a quick calculation does not reveal anything good for black (ie, no tactical tricks after the captures).

Idea 4 – reinforce/defend the attacked square or piece (the black queen).  There are no legal ways to defend the queen.

Idea 5 – counterattack with an equal or greater threat (of winning the queen).  Looking at the EGT chart from earlier we can see that against a threat to your queen, you have one equal target (the enemy queen) and two greater (check and a mate threat).  In this position we have one move that creates an equal threat (1…Ra6), but we have zero checks and cannot create any mate threats.

This process has generated two specific candidate moves:

The next step is to calculate both of those candidates.  How to pick which one to calculate first?  We can either start with the most forcing, or the easiest to refute.  Let’s start with the most forcing, the capture 1…Qxb8:

After the natural 2. Qxb8 Rb3 (2…Rxc4 3. Qxa7) 3. Kf2 Rxa2+  white has an advantage in material and activity.  White now has a one point material advantage (Queen vs Rook and Knight), and white’s passed pawn is making good progress while black’s pieces are rather passively placed.  The white king is slightly encircled but there are no real threats because black’s pieces aren’t coordinated and the black king is exposed.  The black knight has a check, but it only puts the knight further away from the action.  Black should reject this line.

That only leaves one other candidate move.  At this point you might say, why calculate the other line?  If we only have two candidate moves, and have determined one is bad why calculate the second?  We could certainly do that IF the candidate we calculated first lead to checkmate.  Then there would be no doubt about it, anything must be better than getting mated so just play the second candidate and calculate later.  But the evaluation was not absolute.  Yes it is bad for black, but it wasn't checkmate, and if our second candidate also turns out to be bad for black we might have to pick from the "least bad" candidate.  So we can't completely reject the candidate just yet.

So on to the next candidate move -- the equal counterattack against white’s queen with 1…Ra6:

Here we go with the wild world of counterattacks. Again we need to keep in mind all three goals when moving through these variations – WIN, DRAW, or DEFEND.  I mentioned in the last post I like to start by looking for draws by stalemate first because it is easiest to eliminate.  A quick glance at this position shows black does not have many pawn moves, but his king has plenty of squares.  So stalemate is not a defensive option for black.

As noted above black has a material lead of two points black and would WIN if white allows equal trades, which means white wants to avoid:

2. Rxa8 Rxd6 3. Rxa7 Rd2!? Even though black’s material advantage is now only one point (two white pawns vs a black knight) and white has two passed pawns, black’s rook and knight are positioned well to capture them, and white’s king is out of play.  For a beginner this might be a tough position to win as black, but black is indeed winning and white is hoping for a draw.  So white would reject the equal trade of queens starting with 2. Rxa8.  White should also reject the equal trade of rooks:

2. Qxa6 Qxb8 which is even worse for white than the equal trade of queens!

We have looked at both piece captures to prove they are bad for white (since black WINs), but what other candidate moves does white have?  We have to keep in mind the material/activity balance.   If he pursues equal trades, he will lose.  If white allows the material balance to remain the same he will lose for example, any move by white’s queen to escape from black’s rook will allow the black queen to also escape from a8.  All of this is good for black, but bad for white.

White does have another capture, which also happens to be the most forcing move on the board -- the capture check:

2. Qxf6+! Kxf6 (Rxf6?! and the rook is now passive) 3. Rxa8 Ra3!?4. Kf2 Rxa2+ and as Tarrasch said “all rook endgames are drawn.”  Black’s rook is more active than white’s, but it is only a tiny edge and this is a draw.  For white, this appears to be his best option and I see no other candidate moves that are better for white (all others lose!).

Here is our final chart:

Conclusion.  This process has shown us that black has only two candidate moves to consider in the initial position -- one of them leads to a loss if white plays properly, and the other leads to a drawn endgame.  So black's best choice is to try for the draw.

This is the process you should be able to do mentally:  prioritize the threats, use the five defensive ideas to search for specific candidate moves, calculate each one completely, and then pick the best variation based on the final evaluation.

In the next post we will look at positions where the best defense is draw by repetition.

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