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1 The Exchange The simplest exchanges are between the same pieces: knight for knight, color like bishops, rook for rook, and queen for queen. Any other exchange leads to imbalanced positions (see Pieces Value and Positions with material equivalence from Month 1). Now, let s do a categorization of the exchanges after their basic objective (however, a combination of them being also possible): 1. Tactics; 2. Qualitative changes on the position; 3. Simplification of the position. 1. Tactics In most of the cases, after a player takes a piece, the opponent is forced to take back so his next move is forced. Also, this trade eliminates some defenders, opens some lines, attracts pieces in maybe unwanted positions all these being a possible source for tactics. In this tensioned position, there are many possible exchanges: Ne5xd7, Ne5xc6, Nd2xe4, Bd3xe4, c4xd5, d4xc5. Also, White has to consider Black s possible replies: Nc6xe5, Bd6xe5, Ne4xd2, c5xd4, d5xc4. Strategically, any exchange doesn t bring any advantage to White so he continued with 1.f2-f3. However, White could win a pawn with: 1.Nxd7! Qxd7 2.cxd5 exd5 3.Nxe4 fxe4 4.dxc5 Bxc5 5.Bxe4. After some trades that looked harmless for Black, the d-file became opened, the black queen was attracted on d7 and now the d5- pawn is pinned. 8r+-wq-trk+( 7zpp+l+-zpp' 6-+nvlp+-+& 5+-zppsNp+-% 4-+PzPn+-+$ 3+P+LzP-+-# 2PvL-sN-zPPzP" 1tR-+Q+RmK-! Let s go back to the game after 1.f3. Now it was Black s turn to visualize different positions after the possible trades in the center. After: 1...Nxd2 2.Qxd2 cxd4 3.exd4 Nxe5 4.dxe5 Bc5+ 5.Kh1 Bc6 Black s position is preferable. 1

2 Here, Black s last move was h7-h6. He didn t even consider that White will part with his bishop-pair by 1.Bxf6! After 1 Qxf6, other surprising exchanges followed: 2.Nxc6 Bxc6 3.Bxc6! bxc6. So, White renounced at his fianchettoed bishop too, but not without a concrete idea: 4.Qa4! Now the previous exchanges are clearly explained: in the resulting position, Black cannot defend the c6-pawn with any piece and therefore he is forced to play the ugly: 4 Kd7. After 5.0-0, 6.Rac1 and 7.Rfd1, White has a strong pressure in the center and an attack against the black king. In this position, White had the task to visualize the position after making all the possible trades. 8r+-wqkvl-tr( 7zppzpl+p+-' 6-+nzp-snpzp& vL-% 4-+PsN-+-+$ 3+-sN-+-zP-# 2PzP-+PzPLzP" 1tR-+QmK-+R! Important conclusion: Exchanges are forcing moves that must be calculated like you calculate what happens after a check for example. Also, in complicated positions where we have to calculate lot of variations, the exchanges (besides checks and other direct strong threats) are that forcing moves which we need to calculate first or at least consider in the list of candidate moves. When you calculate an exchange you need to make sure that the exchanged piece will not appear again on the board (a very frequent error in calculation). 2. Qualitative changes on the position When an inactive/bad piece is exchanged for an opponent better one. The comparison between the qualitative values of pieces of the 2 armies offer us concrete directions on what pieces should be exchanged. A very simple and automatic exchange is when an open file appears and no player wants to leave opponent rooks controlling that file. The same is when a bishop controls a long diagonal, or a knight gets a centralized position: the opponent wants to neutralize those pieces by exchanges. In many opening systems, Black has a bad piece and one of the opening battles is around the exchange of that bad piece. For example, the bad light-square bishop from French that Black often tries to exchange with the white one by Bc8-d7-b5 or the Stonewall bishop that comes into play via: Bc8-d7-e8-h5 only to be exchanged. Sometimes, the battle for keeping / exchanging a good piece is more complicated. Let s see the following example: 2

3 A relative complicate position with all the pieces on the board. The opposite castles increase the value of open lines, so the quality value of bishops and rooks. It is easy to see that Black has a very powerful bishop on e5 which defends the kingside, the d6- pawn and creates pressure on the White s queenside. With his last move, 1.Nc2-e1, White intends to exchange Black s best piece. In the next sequence of moves, both White and Black will fight against / for this bishop: 1 bxc4! 1 Ne8 2.Nd3 Bg7 doesn t work because the f4- pawn is hanging. 2.Bxc4 Na5 3.Qc2 Nxc4 4.Qxc4 Ne8! Makes room for the bishop on g7 and also brings the knight on b5 to prevent Bf2-e1-c3. 5.Nd3 Bg7 6.Be1 Nc7! XHGFEDCBAY 1RtR-sN-+K+! 2+-vLLwQ-zPP" 3-+P+-+-+# 4zPPzpP+P+-$ 5-+-vlNzpp+% 6+p+lzpn+p& 7psn-+-+-+' 8+ktr-wq-+r( xhgfedcbay Black is to move Now, White cannot play 7.Bc3 because of Bxc3 8.Qxc3 Nxd5. The strong dark-square bishop is saved as Nc7-b5 follows. Also, Black will do another advantageous exchange by Bxd5, White being forced to take back with the pawn Space / Superfluous / Limited pieces In many theoretical articles and books, it is said that the player with more space should avoid (unnecessary) exchanges and the player with less space should look for exchanges. This principle is partially correct but often this is not true. Think for example at the Hedgehog structure where Black stays behind its pawns from the sixth rank. In this structure, Black s counter-play is based on the dynamic of his pieces that may come very lively into play after b6-b5 or d6-d5. In some cases, White, the player with more space, should even look for exchanges which would deprive Black from his counter-play possibilities. Let s see the position from the right (Leko Ivanchuk, 2007). The difference of space of White and Black is obvious, but if you analyze the place and the role of each of Black s pieces, you will notice that they are all safely placed and they do not obstruct each other. XHGFEDCBAY 1K+R+-tR-+! 2zPP+LwQN+P" 3-+PvL-sNP+# 4+-+P+P+-$ sn-+% 6+p+pzpnzpp& 7pvlpwq-+l+' 8+k+-tr-tr-( xhgfedcbay Black has less space, but not superfluous pieces 3

4 So, the connection between space and the principle of looking for / avoiding exchanges needs better thoughts. In the previous diagram, Black had no superfluous pieces, but in the next one (Game 7 Month 5), the things are totally different: If you take all the minor pieces from the board, the position is rather equal. However, here White has 3 minor pieces that do nothing than only limit each other. The seven white pieces find themselves in a ridiculous situation: the knight on e1 has no moves; the knight on c2 has only the possibility to move on a1; the bishop on e2 is able to move eventually around his ax of symmetry; the rook on f1 can move only on f2; the rook on d1 can move only on b1 and c1; the queen resembles his ancestor from the game Strandj, which was able to move only on square in diagonal; the most mobile piece is the king, who has the possibility to move on h1 and f2. XHGFEDCBAY 1-mKRsNR+-+! 2zPP+LwQN+P" 3-+-zP-+P+# 4+-zPp+Pzp-$ 5-+p+Pzp-+% 6+pvl-zp-+p& 7pmkn+-+l+' 8+-trq+-+r( xhgfedcbay 2.3. In some cases, a piece defends important squares. By exchanging that piece, the opponent can take the control of those squares. In the game Karpov Browne, 1972, after the moves 1.c4 c5 2.b3 Nf6 3.Bb2 g6, White made a surprising exchange: 4.Bxf6! and after 4 exf6 5.Nc3 followed by g3 and Bg2, White had a total control over d5. The next step is to play e2-e3 and d2-d4 to open the d- file and to create pressure against the backward Black s d-pawn. In this position from the game Alekhine Nimzowitsch, 1930, White has space advantage on the queenside. Moreover, the qualitative value of the white d6-knight is clearly superior to the limited black b7-bishop. However, the real problem in Black s position is the weakness of the light-squares that White will exploit after trading off the Black s bad bishop. The attack of the light-squares begins by: 1.a5! Black cannot take the pawn: 1 bxa5 2.b5! Nd8 3.Ra5 and the a7-pawns cannot be defended (White will continue with Bd3, 0-0, and Rfa1). 1 Nc8 2.Nxb7! Black s bishop was really bad but he did a good job defending the light-squares. 2 Qxb7 3.a6! 8r+-+-trk+( 7zpl+qsn-zpp' 6-zpnsNp+-+& 5+-+pzPp+-% 4PzP-zP-zP-+$ N+-# 2-+-wQ-+PzP" 1tR-+-mKL+R! 4

5 Taking under control b7, Black remains with few squares on the queenside. Now, White will increase the pressure against the c6-square doubling and then tripling the major pieces on the c-file: 3 Qf7 4.Bb5 N8e h6 6.Rfc1 Rfc8 7.Rc2 Qe8 8.Rac1 Rab8 9.Qe3 Rc7 10.Rc3 Qd7 11.R1c2 Kf8 12.Qc1 Rbc8 13.Ba4 b5 14.Bxb5 Ke8 15.Ba4 Kd8 16.h4! Black is in zugzwang! 16 h5 17.Kh2 g6 18.g Simplification of the position. The exchange usually leads to a simplification of the position and brings the endgame closer. We have again 3 cases: 3.1. The quality value of the remaining pieces increase in importance by any exchange. In this example, we are analyzing the qualitative value of minor pieces of the 2 camps. White s last move was 1.Qg3 threatening to take the g7-pawn. If Black plays now 1 g6?, the White s dark-square bishop will get a new territory of activity around the weaknesses of the black kingside. Black does not like this and furthermore he wants to provoke f2-f4 after which the c1-bishop becomes limited. Black played 1 Ne7! defending indirectly the pawn (2.Qxg7?? Rg8). By 2.f4? White wanted to release his queen from defending the e5-pawn and also to play Bd3 and f4- f5 with an attack. However, the consequence of his move matched Black s intentions c4 Be4!! 8r+-+k+-tr( 7+lwqp+pzpp' 6p+-+p+-+& 5+-zpnzP-+-% $ 3+-zP-+-wQ-# 2P+P+LzPPzP" 1tR-vL-+R+K! Black is to move By this move, Black provokes the exchange of the light-square bishops (f4-f5 is stopped and the c2-pawn is attacked). Even if the Black s light-square bishop looked better than the White s one, this exchange will simplify the position and the difference of quality between the black knight and the white dark-square bishop will gain in importance. 4.Bd3 Nf5 5.Qh3 Qc6 Black does not hurry with the exchange; now the queen will take the place of the bishop as sooner or later White will be forced to make the trade. It is easy to observe that the black knight from f5 controls important squares, especially e3, and White in unable to re-organize his pieces. 6.Bb2 Rfd8 At the next move, Black will play d7-d5 gaining another advantage: the control of the d-file. Black has a strategically won position. 5

6 3.2. Simplification of material is one of the simplest ways to transform a complicate position into a technical won endgame. When having material advantage, better pawn structure (the opponent has long-term weaknesses) or other long-term strategical advantages, the exchanges are the first option that the player with an advantage should look for. This way, the second player will be deprived by counter-play chances. Not unusual exceptions from this rule are the positions with opposite-colored bishops or a pair of rooks where an extra pawn (or even 2 pawns) can be only a draw. Of course, there are also other rarer exceptions like for example: queen + 2 knights against queen, the queens should be not exchanged (2 knights alone cannot deliver mate). Position from the game Zagoriansky Kan, White has the advantage of the bishop-pair in an open position. Also, all his pieces are ideally placed. In this stage when other advantages cannot be gained, there are 2 methods to continue: 1. a direct attack against opponent king or 2. the simplification of the position looking for a technically won endgame. Here, White cannot attack the black king, so he goes for exchanges (of course, after analyzing the resulting position): 1.Nd5! Nxd5 2.exd5 so, by this exchange White gained another advantage, a free pawn. Because of the open files, the rook will be exchanged: 2 Rxc1 3.Rxc1 Ng6 4.Qb6 threatening Rc7, it forces another exchange: 8r+r+-snk+( 7+l+-wqpzp-' 6p+-+-sn-zp& 5+p+-zp-+-% 4-+-+P+-+$ 3zP-sN-wQ-vL-# 2LzP-+-zPPzP" 1+-tRR+-mK-! 4 Rc8 5.Rxc8 Bxc8 6.d6 and in this simple, uncomplicated position, White can exploit his advantages without risks. Position from Mednis Keene, 1975, White to move. Black has a big advantage because of his 2 free connected pawns in the center. White is not able to stop the black pawns, but he finds a very nice simplification of the position, sacrificing a knight for the 2 pawns (irregular exchange): 41.Rd1!! Nxb3 42.Nxe6+ Rxe6 43.Nxd5+ Nxd5 44.Rxd5 The endgame rook + knight versus rook is a draw and Black is not able to keep his h pawn. Of course, White still needs to show a good technique, but from theoretical point of view, he saved the game. This continued: ( 7+-mk-+-+-' 6-sn-+p+-zp& 5+-+ptr-+-% 4-+-sn-sN-+$ 3+PsN-+-+-# PzP" 1+R+-+-mK-! 6

7 44 Kc6 45.Rh5 Nd4 46.g4 Rg6 47.Kf2 Ne6 48.Kg3 Kd6 49.h4 Ke7 50.Rf5 Ng7 51.Ra5 Rd6 52.Ra7+ Kf8 53.Ra8+ Kf7 54.Ra7+ Kg6 55.Ra3 Ne6 56.Rc3 Nd4 57.Ra3 Rb6 58.Ra5 Ne6 59.Ra3 Nc5 60.Ra5 Rb3+ 61.Kg2 Rc3 62.Rb5 Rc4 63.Rb6+ Kg7 64.Kh3 Nd7 65.Rb5 Rc5 66.Rb7 Rd5 67.Ra7 Rd6 68.Ra5 Rd3+ 69.Kg2 Re3 70.Ra7 Re7 71.Kg3 Kf7 72.Ra6 Re6 73.Ra7 Rd6 74.Ra5 Kg6 75.Kh3 Rc6 76.Rd5 Nc5 77.Rd4 Re6 78.Rc4 Nd3 79.Ra4 Re3+ 80.Kg2 Nc5 81.Rc4 Ne6 82.Ra4 Rd3 83.Ra6 Kf7 84.Ra7+ Kg8 85.Ra8+ Kf7 86.Ra7+ Kf6 87.g5+ hxg5 88.hxg5+ Kxg5 89.Re7 Kf5 ½ ½ 3.3. Reducing opponent s initiative / attack In this position from the game Ghinda - Jussupow, 1986, Black has the initiative because: - he can create a free pawn on the a-file - the presence of the opposite colored bishops favors the player in attack who is practically a piece up. Here, after Bf5-e4, White s king will be in real danger. The opposite colored bishops are a factor of unstability in the presence of major pieces, so White will do an excellent maneuver to trade the rooks: 1.Rf3!! Be4 2.Rg3! Even if White will get double pawns on the g-file, Black s initiative is strongly reduced. 2 Rxg3 4.hxg k+( 7+-zpq+-zp-' rzp& 5zpp+pzPl+-% 4-+-zP-+-+$ 3vLPzP-+-+-# 2-+-wQ-+PzP" RmK-! 7