When a player has achieved a material advantage, the person may feel that he or she deserves to win. This often makes the player get careless and perhaps even lose.
Here's a position from LevinLevy (Shore High School Chess League Individual Championship [NJ, USA], 1973), with White to move. Decide on a move for White before you read past the following diagram.
It may seem that White, now ahead by a rook for a pawn, should win easily. Decide on a move for Black before reading further.
This move not only attacks White's d1-rook but has allowed Black's rook to make a "discovered attack" against White's d6-knight. Decide on a move for White before reading further.
White failed to realize that his d6-knight was also attacked. Black naturally played 27...Rxd6 to get almost even in points. Black eventually won.
Let's return to the position in the first diagram, to see how White could have done better.
Instead of getting careless at his 26th move, White should have continued looking for ways for Black to check or capture. In my answer to Question #11 under "Selected Questions and Answers," I said that a player should try to find the following types of "tactical" moves:
Let's start with number 1. Try to find any way that White could have checked at his 26th move. Here again is the position.
White has no way to check right away. Let's go to number 2. Try to find any way that White could have captured. Don't worry yet about whether the capture is good or bad for White. Good captures sometimes seem bad at first.
White had the following ways to capture: 26. Rxd5, 26. Nxa6, 26. Nxd7, 26. Nxe6, or 26. Nxf5.
Let's look at each of those captures. 26. Rxd5 would have lost the rook by 26...exd5. 26. Nxa6 would allow 26...Ba4, which happened in the game. 26. Nxd7 would get rid of that bishop, and Black could play 26...Rxd7 for an even trade. 26. Nxe6 would lose the knight to 26...Bxe6. 26. Nxf5 would lose the knight to 26...exf5 or 26...gxf5.
This means that the only capture that wouldn't be bad for White is 26. Nxd7. Although this leads to an even trade after 26...Rxd7, even trades tend to favor the player who is ahead in material. This is because as the chessboard gets more empty, the chessmen still on the board have more places to go. Having more material means your pieces will have more places to go than the opponent's.
Now we'll go to number 3 and pretend it's Black's move instead of White's. Let's see how Black could check in one move. Here's the position again.
Black's only check would be 26...Bd4+, but White could capture the bishop by 27. Rxd4. This means that Black had no good check.
Now we'll look at number 4, ways for Black to capture in one move. Actually, there is no way for Black to capture in one move.
Let's go to number 5, ways for White to check in two moves, assuming that Black didn't try to stop it. Here's the position again.
The only way for White to check in two moves would be to play 26. Rb8 and 27. Rxd8+, but Black obviously would play 26...Rxb8 to capture White's rook.
Going to number 6, there are many ways for White to capture in two moves, if Black doesn't stop it. Try to find them all and then decide which of those moves would win points for White no matter what Black does. Here's the position again.
The move 26. Ndb7 would attack Black's rook, which is the only piece protecting the d7-bishop and stopping White's c5-knight from capturing that bishop for free. If Black plays 26...Rb8, White can win the bishop by playing 27. Nxd7. For Black to then play 27...Rxb7 would be bad because White could capture the rook by playing 28. Rxb7.
After 26. Ndb7, Black can try other moves, but none of them will stop White from winning at least three points. This shows that even after you are ahead in material, you should keep looking for checks or captures.
As we saw, White played 26. Nxa6, allowing 26...Ba4. Let's think about what White might have done after that. Here's the position after 26...Ba4.
Since two of White's pieces are attacked, he should look for a safe way to move one of them to where it attacks a Black piece. Try to find the ways to do this before you continue reading.
White's d1-rook could attack Black's a4-bishop by playing 27. Rd4, or White's d6-knight could attack Black's rook by moving to either the b7-square or the f7-square. 27. Rd4 would lose the rook to 27...Bxd4+, and 27. Nf7 would lose the knight to 27...Kxf7. But 27. Nb7 seems safe. Here's the position after 27. Nb7.
Now, if Black captures White's rook by 27...Bxd1, White can capture Black's rook by 28. Nxd8. If Black plays 27...Rc8 (a safe square that's also on an "open file"), then White's d1-rook can move away. Black should instead try to move his rook to where it is about to safely capture a White piece. This would again put two of White's pieces under attack. Think about how to do this before reading further.
Playing 27...Rb8 wouldn't help Black because White's b7-knight is defended by White's b1-rook. But 27...Ra8 would attack White's a6-knight. Here's the position after 27...Ra8. Before looking below the diagram, think about what White should do now.
White should now move his attacked a6-knight so that it attacks Black's rook, by playing 28. Nc7.
You can probably guess what Black should do now. He should play 28...Rc8, attacking White's c7-knight. Here's the position after 28...Rc8. Before you read past this diagram, think about what White should do.
White's d1-rook and c7-knight have no moves that safely attack a Black piece. But White's attacked rook can now move to where it protects White's attacked knight. Do you see how? By playing 29. Rdc1. Here's the position after 29. Rdc1.
White's c1-rook needs to keep protecting the c7-knight, but right now that rook has no safe moves along the c-file. (What's wrong with moving the rook to the c5-square? It would allow ...Bd4+, forking White's rook and king.) Black could try to take advantage of this by attacking that rookby 29...Bh6, leading to the following position.
Black's last move has given up control of the c3-square. But let's suppose that instead of going there with his c1-rook, White plays 30. Nd6, intending to answer 30...Bxc1 with 31. Nxc8. The position after 30. Nd6 is shown below.
Decide what you think Black should do. He should play 30...Rd8, so that two of White's pieces are attacked. See next diagram.
Now, if White plays 31. Nb7, Black can "repeat the position" by playing 31...Rb8. Since White is ahead by four points, he shouldn't be satisfied to draw. But it does seem that White finally has to either give up his c1-rook for Black's h6-bishop or give up his d6-knight for free. Which choice would lose fewer points for White?
Giving up the rook for a bishop would lose two points, but giving up the knight for free would lose three points. This means that it's better to give up the rook, which will still leave White ahead by two points. Also, it's good to get rid of Black's h6-bishop, which seems worth more than three points because it can reach almost every square on the board. This is because almost all the pawns are on light squares.
If White doesn't want to lose the d6-knight, it has to move away. The only safe place is the b5-square. 31. Ndb5 leads to the following diagram.
Black should then take the rook by 31...Bxc1, which White would recapture by 32. Rxc1, leading to the following position.
White is still two points ahead and should eventually win.
This showed that sometimes you have to think very hard even when you are far ahead in material.
The following position is from EldridgeLevin (South Jersey Open, 1975). It's White's move.
Decide on a move for White before looking at the next diagram.
Black is ahead by three points, yet White is offering to exchange rooks. Should Black trade rooks? Decide before reading further.
White's b-pawn is now attacked by two Black pieces: the d6-knight and the b2-rook. It is defended only by White's bishop. Decide what White should play, and then read on.
Now we see why White moved a rook to the a-file. He wanted to then move the rook to the a7-square.
To get out of check safely, Black must move his king to the back "rank." Black wanted his f-pawn protected so that he could later play ...Nxb5. Therefore, Black played 31...Ke8.
Does any Black piece seem to be worth fewer points than it should be? How about the h8-rook? This piece would be good to have on the c-file, but instead it's asleep in the corner. Black didn't realize that by trying to win the b-pawn (one point), he would be blocking his h8-rook, which is like giving up more than one point.
Also, if Black were to "develop" the b8-knight by playing ...Nd7 (the only safe square for that piece), White could play Ra8+ and then Rxh8 after Black's king moves out of check. This means that Black's trying to win the b-pawn has tied up both the h8-rook and the b8-knight.
Here again is the position after White played 30. Ra1. Think about what Black should have played instead of 30...Rb2.
Black would like to play ...Rc8 before White's a1-rook can go to a7. Therefore, he should play 30...Rxa1, which makes White wait a move before he can play Ra7. After White replies 31. Rxa1, Black can play 31...Rc8, leading to the next diagram.
If White were to now play Ra7+, Black's king could retreat without causing harm. Actually, moving the king would help Black by letting the b8-knight come to the d7-square.
These two examples have shown that when a player is ahead or behind in material, the rest of the game should be played almost as though material is even. This means you should do the following:
Here's the only difference when you are ahead in material. If making an even trade is one of your best possible moves, you should make the trade.
Here's the only difference when you are behind in material. If you have a possible move at least as good as making an even trade, you should not make the trade.