1.

[Okay. Now let's take a look at how pawn structure determines whether the game is an open game or a closed game, and then we'll see how that affects your pieces. First of all, an open game is when the central pawn structure is airy, ripe with possibility, and not locked down, like in this position. This is an open game. Diagonals and files are not blocked and pieces have tremendous dynamic potential. A general rule with many exceptions is that bishops are a little stronger than knights in open games, while knights sometimes have an edge in locked down pawn structures in which time is not of the essence and their unique ability to jump over pieces becomes especially handy.

{B:rnbqkbnr/pppppppp/32/PPPPPPPP/RNBQKBNR}{D:8000}{B:r2r2k1/1bqpb1pp/p1n1pn2/1p6/8/1PNB1N2/PBP1QPPP/3RR1K1}{D:2000}{H:a6b5d7e6g7h7}{H:a2b3c2f2g2h2}{D:6000}{B:8/3p2pp/p3p3/1p6/8/1P6/P1P2PPP/8}{D:1500}{A:Tb7f3}{A:Te7a3}{A:Te7h4}{A:Tb2f6}{A:Td3h7}{D:250}{H2:c3c4c5c6c7c8}{D:250}{H:d1d2d3d4d5d6}{D:250}{H2:e1e2e3e4e5}{D:250}{H:f3f4f5f6f7f8}{D:2500}{R}{H0:d1d2d3d4d5d6e1e2e3e4e5}{H0:c3c4c5c6c7c8f3f4f5f6f7f8}{D:1000}{C}{B:r2r2k1/1bqpb1pp/p1n1pn2/1p6/8/1PNB1N2/PBP1QPPP/3RR1K1}{D:2000}{H2:b2b7d3e7}{D:1000}{H:c3c6f3f6}{W:j33e27}{C}

]

2.

[

{B:r2r2k1/1bqpb1pp/p1n1pn2/1p6/8/1PNB1N2/PBP1QPPP/3RR1K1 b}{V:{SAVE}Along those lines, what is black's best move here?

{W:j33e28};

$Well, we know we have an open game, so knight B4 is very strong. The white bishop cannot escape the trade, and so black will have improved his position by eliminating a bishop in an open game. Without understanding how a pawn structure affects the power of the pieces, we would never have know where to look for the best move in this type of position. We work from our principles.

  {D:2000}{S:c6b4}{A:Cb4d3}

  {D:3000}{H:c4d3e4f5g6}{A:Tb5c4}{A:Tf6e4}{A:Te6f5}{A:Th7g6}

  {W:j33e29}{W:sil1000}{J}

$c6b4;Well, we know we have an open game, so knight B4 is very strong. The white bishop cannot escape the trade, and so black will have improved his position by eliminating a bishop in an open game. Without understanding how a pawn structure affects the power of the pieces, we would never have know where to look for the best move in this type of position. We work from our principles.

Good job!

  {D:2500}{A:Cb4d3}

  {D:2500}{H:c4d3e4f5g6}{A:Tb5c4}{A:Tf6e4}{A:Te6f5}{A:Th7g6}

  {W:j33e29}{W:sil500}{W:goodjob}{W:sil1000}{J};

$c No, that's not quite it...

  {W:notquiteit}{RETRY};

Look for a knight move.

}

]

3.

[Now, let's take a look at a closed game. This is a closed game because the central pawn structure is completely locked down. There is, however, a lot of play in the position. The B and H files are open, which means there's potential for both king's side and queen's side attacks for either side. Remember how I said that sometimes knights are better in closed games? It's white's move here. What would you play?

{B:r3r1k1/2qn2b1/3p4/p1pPp1p1/P3PpP1/2PB1P2/3NQ3/1R2R1K1 w}{D:4000}{H:d6e5f4g5}{H2:d5e4f3g4}{D:2500}{C}{D:2500}{H:b1b2b3b4b5b6b7b8h1h2h3h4h5h6h7h8}{D:5500}{C}{W:j33e30}{V:{SAVE}Now, let's take a look at a closed game. This is a closed game because the central pawn structure is completely locked down. There is, however, a lot of play in the position. The B and H files are open, which means there's potential for both king's side and queen's side attacks for either side. Remember how I said that sometimes knights are better in closed games? It's white's move here. What would you play?;

$Here white can play bishop B5, pinning the knight on D7 to the rook.

  {S:d3b5}{D:2000}{A:Cb5d7}{A:Dd7e8}{W:j33e31}{W:sil1000}{J}

$d3b5;That's right! 

Here white can play bishop B5, pinning the knight on D7 to the rook.

  {W:thatsright}{W:sil500}

  {D:2000}{A:Cb5d7}{A:Dd7e8}{W:j33e31}{W:sil1000}{J};

$c That's not quite right. Try again.

  {W:notquiteit}{RETRY};

Force the trade of one of your opponent's active pieces. Keep in mind this is a closed game.

}

]

4.

[After rook D8, bishop takes D7, rook takes D7, let's evaluate the position. The only material difference is that black has a bishop for white's knight. Which do you prefer? How do you feel about that bishop? It turns out that white's position is better, because the game is closed and black's bishop is locked in by its own pawns. If it were a light squared bishop, say on A6, then the evaluation would look quite different. Pawn structure is the crucial determinant of the strength and weakness of bishops.

{B:r3r1k1/2qn2b1/3p4/pBpPp1p1/P3PpP1/2P2P2/3NQ3/1R2R1K1 w}{D:300}{R}{S:e8d8}{D:700}{S:b5d7}{D:1000}{S:d8d7}{D:5000}{H:g7}{D:1000}{H:d2}{D:4000}{C}{D:4000}{H:d6e5f4g5}{A:Tg7e5}{A:Tg7h6}{A:Tg7f8}{D:2000}{C}{R}{D:1500}{S:g7a6}{D:2000}{H2:a6b5c4d3e2f1b7c8}{D:2000}{C}{W:j33e32}

]

5.

[Here are some principles that can guide your evaluations. First of all, bishops prefer open games to closed games. Also, a bishop is good if its fixed or immobile pawns are on the opposite color, so they don't block its moves, and the opponent's fixed pawns are on the same color, providing targets. You want a bishop to have targets, not to be hemmed in by its own teammates. Take a look at this position.

{B:rnbqkbnr/pppppppp/32/PPPPPPPP/RNBQKBNR}{D:3000}{B:r2r2k1/1bqpb1pp/p1n1pn2/1p6/8/1PNB1N2/PBP1QPPP/3RR1K1}{D:1000}{H2:d3}{H:e4f5g6c4}{D:500}{N2:b2}{H:a1a3c1c3d4e5f6}{D:500}{N2:b7}{H:c6d5e4f3}{D:500}{N2:e7}{H:a3b4c5d6f8f6g5h4}{D:1500}{B:1r3r2/6k1/2b3p1/1p1p3p/pP1P4/P2B2P1/5P1P/1R3RK1}{D:1000}{H2:d3}{D:1000}{H:a3b4d4f2g3h2}{D:5000}{N:a4b5d5g6h5}{H2:d3}{D:3000}{A:Cd3b5}{A:Cd3g6}{D:500}{G:WBc2}{G:WBf3}{A:Cc2a4}{A:Cf3h5}{A:Cf3d5}{D:4500}{B:8/8/1b6/p3k3/P4p1p/3K1P1P/3B4/8}{W:j33e33}

]

6.

[

{B:8/8/1b6/p3k3/P4p1p/3K1P1P/3B4/8}{QB:With what you now know about bishops, who's better here? White or black?{W:j33e34};

White;That's right. White is better, because black has all the weaknesses and white has all the targets.

  {W:thatsright}{W:sil500}{D:1500}{H:b6}{H:a5f4h4}

  {D:1200}{G:WBe1}{A:Cd2a5}{A:Cd2f4}{A:De1h4}{W:j33e35}{W:sil1000}{J};

Black;That's not quite it. White is better, because black has all the weaknesses and white has all the targets.

  {W:notquiteit}{W:sil500}{D:1500}{H:b6}{H:a5f4h4}

  {D:1200}{G:WBe1}{A:Cd2a5}{A:Cd2f4}{A:De1h4}{W:j33e35}{W:sil1000}{J}

}

]

7.

[A subtlety about this principle, which is a distinction that is slightly more advanced than this course - but I'll tell you anyway - is that in the middle game or opening, you should focus on central pawns that are fixed when evaluating bishops, while in the endgame, you should focus on all pawns. This is an idea to keep in the back of your mind for a few years down the road.

{B:rnbqkbnr/pppppppp/32/PPPPPPPP/RNBQKBNR}{D:5000}{B:r3r1k1/2qn2b1/3p4/p1pPp1p1/P3PpP1/2PB1P2/3NQ3/1R2R1K1}{D:2000}{H:d6e5f4g5}{H2:d5e4f3g4}{D:3000}{C}{B:8/8/1b6/p3k3/P4p1p/3K1P1P/3B4/8}{D:1000}{H:a5f4h4}{H2:a4f3h3}{D:3000}{C}{W:j33e36}

]

8.

[

{B:1rr5/4bq1k/4p2p/3pPp2/p1pP1P2/P1P2Q2/2R1K2P/2BR4}{QB:Who's better here? White or black?{W:j33e37};

White;No that's not quite it. 

Black is better, because he has the good bishop. All white's pawns are on dark squares, locking his bishop, and black has tons of targets. White has none.

  {W:notquiteit}{W:sil500}{D:1500}{H2:e7}{A:Ce7a3}{A:Te7h4}

  {D:1500}{H:a3c3d4e5f4h2}{D:2000}{H:c1}{A:Tc1a3}{A:Tc1f4}

  {D:3500}{C}{R}{W:j33e38}{W:sil1000}{J};

Black;Good job! 

Black is better, because he has the good bishop. All white's pawns are on dark squares, locking his bishop, and black has tons of targets. White has none.

  {W:gg}{W:sil500}{D:1500}{H2:e7}{A:Ce7a3}{A:Te7h4}

  {D:1500}{H:a3c3d4e5f4h2}{D:2000}{H:c1}{A:Tc1a3}{A:Tc1f4}

  {D:3500}{C}{R}{W:j33e38}{W:sil1000}{J}

}

]

9.

[

{B:3rr1k1/pp1qn1bp/2p1b1p1/2Pp4/3Pp3/1PN1P3/PB1QB1PP/1KR2R2 b}{V:{SAVE}It's black to move here. What's your best move?{W:j33e39};

$Bishop G4, and excellent strategical decision, trading your bad bishop for white's good bishop, and black takes the edge. 

  {S:e6g4}{A:Cg4e2}{A:Gd7g4}{D:4500}{C}{R}{S:e2g4}{D:500}{S:d7g4}

  {D:700}{H2:h5g4f3e2d1}{A:Cg4g2}{W:j33e40}{W:sil1000}{J}

$e6g4;Bishop G4, and excellent strategical decision, trading your bad bishop for white's good bishop, and black takes the edge. 

  {D:500}{A:Cg4e2}{A:Gd7g4}{D:4000}{C}{R}{S:e2g4}{D:500}{S:d7g4}

  {D:700}{H2:h5g4f3e2d1}{A:Cg4g2}{W:j33e40}{W:sil1000}{J};

$c This is not the best move.{W:notbest}{RETRY};

Try to exchange one of your inactive pieces for one of your opponent's that's much more active.

}

]

10.

[So remember, when comparing bishops and knights, bishops are usually a little better in open games, and knights are usually a little better in closed games, and when comparing bishops with other bishops, a good bishop is one that has lots of targets. If you have a light squared bishop, you want your pawns for the most part to be on the dark squares, not getting in the way, and you want your opponent's pawns to be on the same color as your bishop. Understanding what makes a bishop good is critical to knowing what and when to trade.

{B:6k1/1pp2pp1/p1np1n1p/8/1P4P1/PB1P1K1P/1B6/8}{D:3000}{H:b2}{H2:b3}{D:1000}{A:Cb3f7}{A:Cb2f6}{H:a1c3d4e5}{H2:a2c4d5e6}{D:1000}{B:7k/1n4p1/p1p1n2p/P1Pp1p2/3PpP2/1B2P3/1B4PP/7K}{H:b7e6}{D:1000}{A:Cb7a5}{A:Cb7c5}{A:Ce6d4}{A:Ce6f4}{D:2000}{B:8/1b6/p3k3/P4p1p/3K1P1P/3B4/8/8}{D:2000}{H2:d3}{D:1000}{G:WBe2}{A:Cd3a6}{A:Cd3f5}{A:De2h5}{D:1000}{C}{R}{O}{D:500}{H2:d3}{D:1000}{H:a5f4h4}{D:4000}{N:a6f5h5}{D:3000}{C}{W:j33e41}

]

