White wins the duel of the Queens.

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. a3 Bxc3+ 5. bxc3 d5 6. cxd5 exd5 7. e3 O-O 8. Bd3 b6 9. Ne2 Ba6 10. O-O Bxd3 11. Qxd3 c5 12. Ng3 Re8 13. Bb2 c4 14. Qc2 Nc6 15. Rae1 b5 16. f3 a5 17. e4 b4 18. e5 Nd7 19. f4 Qb6 20. Qd2 g6 21. Kh1 f5 22. exf6 Nxf6 23. f5 Rxe1 24. Rxe1 bxc3 25. Bxc3 Kg7? 25... Re8 contests the file. 26. h3 26. Qg5! threatens fxg6 followed by Nf5+ and an attack on the dark squares, so Black has to admit his mistake and play 26... Kf7 26... Re8 26... Nd8 is needed to 'greet' the wQ, should she land on g5. 27. Rxe8 27. Rf1! gives Black difficulty holding on to both his Kingside and a5 pawn. 27... Qd8 28. fxg6 hxg6 29. Qg5 sets up bothersome N checks on h5/f5, which can't be evaded by 29... Kf7 due to 30. h4 (with the idea of simply opening lines) 30... Rh8? 31. Ne4! dxe4 32. d5 with a decisive assault on the pinned N. 27... Nxe8= 28. Qg5 Nf6 29. fxg6 Qb1+ 30. Kh2 hxg6 31. Bd2 Ne7? 32. Bf4 32. Nh5+! Nxh5 33. Qxe7+ Kh8 34. Qe5+ picks up a valuable center pawn. 32... Neg8 33. Be5 Kf7 34. Ne2 Qd3 35. Nf4 Qf5 36. Qg3 Nh5 36... g5 kicks the N off a good square. 37. Nxh5 Qxh5 38. Qc3 a4 39. Qa5 6n1/5k2/6p1/Q2pB2q/p1pP4/P6P/6PK/8 b - - 0 39 39... Qd1?? Saving the wrong pawn. 39... Ne7 40. Qxd5+ Kf8 41. Qxc4 41. Qd8+ Kf7 42. d5 is the simplest path to victory. The advance of the d-pawn also helps attack the bK. This is why Black's 39th was a huge error. 41... Ne7 42. Bd6 Ke8 43. Qe6 1-0 [Ryan/Fritz 9]

The punishment for dropping even a single pawn can be quite severe.

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e5 7. Nb3 Be7 8. a4 O-O 9. O-O Be6 10. f4 exf4 11. Bxf4 Qc7 12. Kh1 Nbd7 13. Nd4 Last book move 13... Rac8 14. Nf5 Bxf5 15. exf5 Ne5 16. Qe1 Rfe8 17. Rd1 Bf8 17... Nc4 is a standard move in these types of positions to get White to trade one of the Bishops. 18. Qg3 b5? Inexplicably dropping a pawn. 18... Qb6 19. axb5 axb5?! 19... Qb8 20. Rb1 axb5 21. Bxb5 Red8 puts up more resistance. 20. Bxb5 Red8 21. Bg5 Kh8 21... Be7? 22. Bxf6 Bxf6 23. Nd5 wins a piece. 22. Bxf6 gxf6 23. Nd5 Qxc2 24. Nxf6 Be7? 2rr3k/4bp1p/3p1N2/1B2nP2/8/6Q1/1Pq3PP/3R1R1K w - - 0 25 The wrong direction. 24... Bg7 25. Qh4 h6 holds out longer. 25. Qh4 Kg7 25... Bxf6 is answered convincingly by 26. Qxf6+ Kg8 27. Qg5+ Kh8 28. Rc1! Qe4 29. Qf6+ Kg8 and now the "Rooklift" 30. Rc3 decides matters. 26. Qxh7+ Kxf6 27. Qh6+ 1-0 [Ryan/Fritz 9]

Black's extra pawn is just enough to win the endgame.

1. d4 e6 2. c4 d6 3. Nc3 c6 4. e4 Nf6 5. Nf3 Qc7 Fritz's book prefers 5... Be7 , preparing to castle, and not committing the Q so early. 6. Be2 e5 7. O-O Be7 8. h3 Nbd7 9. Be3 O-O 10. a4 a5 11. Ne1 b6 12. f4 12. d5 is an intere sting alternative, with the idea of eventually exchanging on c6 and gaining b5 or d5 as a support point for the Nc3. 12... Bb7 13. Nf3 Rfe8 14. fxe5 dxe5 15. dxe5 Nxe5 16. Nxe5 Qxe5 17. Bd4 r3r1k1/1b2bppp/1pp2n2/p3q3/P1PBP3/2N4P/1P2B1P1/R2Q1RK1 b - - 0 17 17. Rf5 relieves some pressure on e4. 17. Bxb6 c5 18. Rf5 Qe6 19. Bc7 Nxe4 only trades a wing pawn for a center pawn. 17... Bc5! Alertly winning a central pawn. 18. Bxc5 Qxc5+ 19. Kh1 Nxe4 20. Nxe4 Rxe4 21. Qd3 21. Qc2 discourages the doubling of Rooks. 21... Rae8 22. Bd3 21... Re3 22. Qd7 Re7 23. Qg4 Rae8 24. Bd3 Bc8 25. Qd1 Qg5 26. Ra3? Re3 27. Bc2 g6? He should not exchange his strong R for White's offside counterpart. 27... Re2 is a superior choice. 28. Rxe3 Rxe3 29. Rf3 Be6 29... Rxf3 30. Qxf3 Qc1+ 31. Bd1 Qxc4 secures a solid 2-pawn edge. 30. Rxe3 Qxe3 31. b3 h5 32. Qd3 Qg5 33. Bd1 Qc5 34. Bf3 Kh7 35. Qe4 A pawn down, White should not trade Q's, which represent his best drawing chance. The resulting Bishop ending looks won for Black. 35... b5 36. Qxc6 Qxc6 37. Bxc6 bxc4 38. bxc4 Bxc4 39. Kg1 Kg7 40. Kf2 Kf6 41. Ke3 Ke5 42. Be8? Pointless. 42. h4 gets some pawns off the light squares, and out of range of the enemy Bishop. 42... g5 43. Bc6 f5 43... Bd5 trades the Bishops, or wins another pawn, after which White could resign. 44. Bd7 f4+ 45. Kf2 Be6 46. Be8 h4 Finally fixing all the White pawns on light squares. The game is essentially over. 47. Bb5 Kd4 48. Kf3 Bd5+ 49. Kf2 Kc5 50. Be2 Kb4 51. Bb5 Bb3 52. Kf3 Bxa4 53. Bd3 Kc3 54. Bf5 Bc6+ 55. Kg4 Bxg2 56. Kxg5 f3 57. Bd7 f2 0-1 [Ryan/Fritz 9]

White wins an instructive Bishop endgame.

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 Qc7 6. Be3 a6 7. Qd2 b5 8. f3 Nf6 9. O-O-O b4 10. Nce2 d5 11. Nxc6 Qxc6 12. exd5 Nxd5 If Black wants the chance to play a middlegame, he should prefer 12... Qxd5 13. Nf4 Qa5= 13. Nf4 Bb7 14. Nxd5 Qxd5 14... exd5 15. Bd4 stunts K-side development and opens the e-file. 15. Bc4 Qxd2+ 16. Rxd2 Be7 17. Rhd1 Bc6 18. f4 h5 19. g3 Bf3 20. Be2 Bxe2 21. Rxe2 Rd8 22. Red2 O-O 23. Rd7 Rfe8? Losing a pawn. 23... Bf6 24. Ra7 Ra8 25. Rdd7 Bf6 26. Rxf7 a5 27. Rxa8 Rxa8 28. Ra7 Rxa7 29. Bxa7 Bd8 Black should consider 29... g5 , trading pawns and slightly increasing drawing chances (less targets for White to hit). 30. Kd2 Kf7 31. Kd3 Kg6 32. Ke4 Bc7 33. c4 bxc3 34. bxc3 Kf7 35. c4 Ke7 36. Bd4 36. c5! and 37.Bb6 makes further inroads into Black's camp. He can't avoid the Bishop exchange: 36... a4 37. Bb6 Bb8 38. c6 wins easily. Instead, White ends up working much harder for the point. 36... g6 37. c5 Kd7 38. Be5 Bd8 39. Bd6 Bf6 40. Be5 Be7 41. Bc3 a4 42. Bb4 Bf6 43. Kd3 Kc6 44. Kc4 h4 45. Be1 hxg3 46. hxg3 Be7 47. Bf2 g5 48. Kb4? This throws away the win, because White no longer gets a passed pawn on the K-side. 48. fxg5 turns g3 into a passed pawn. 48... gxf4 49. gxf4 8/4b3/2k1p3/2P5/pK3P2/8/P4B2/8 b - - 0 49 49... Kd5? Turns the c-pawn loose and loses quickly. Correct is 49... Bf8 , intending ...Bh6. 50. Kxa4 (50. Bd4 a3 only delays it one move) 50... Bh6 51. Be3 e5 and Black can easily hold against the a- and c-pawns. 50. Kxa4 Ke4 50... Kc6 51. Kb4 Bf8 52. Bd4! and Black is one disastrous move too late to play ...Bh6. 51. c6 Bd8 52. Kb5 Bc7 53. Bb6 Bxf4 1-0 [Ryan/Fritz 9]

Ratner survived a 4th round scare...

1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. d4 O-O 6. Be2 Nbd7 7. O-O e5 8. Be3 Re8 9. d5 h6 Book moves 9... Ng4 and 9... Nh5 prep the usual ...f5 advance immediately. 10. Ne1 Nc5 11. f3 a5 12. b3 Nh5 13. Nd3 Nxd3 14. Bxd3 Nf4 15. Re1 f5 16. c5 Nxd3 17. Qxd3 f4 18. Bf2 g5?! The computer, obviously unaware that it's not supposed to play on the opponent's side of the board, and aware that Black's attack is going a bit too slowly, prefers 18... dxc5 19. Bxc5 c6 with a slight edge to White. One example of the difficulty he faces in improving his position is 20. Na4 cxd5 21. Nb6 Bf8! 22. Qb5 Ra6 23. Nxd5 Bd7 24. Qc4 Bxc5+ 25. Qxc5 Rc6 . 19. cxd6 cxd6 20. Rac1 g4 21. Kh1 Bf8? r1bqrbk1/1p6/3p3p/p2Pp3/4Ppp1/1PNQ1P2/ P4BPP/2R1R2K w - - 0 22 Boxing the Rook in loses material. 21... gxf3 22. Nb5 Re7 22... Rb8 is just a postponement. 23. fxg4 Bxg4 24. Nc7 23. Rc2? Not only missing a win of material, but allowing Black to get his attack back on track. 23. Bh4 23... Rg7 24. Rec1 g3 25. Bg1 25. Nc7!? Rxc7 26. Rxc7 gxf2 27. Qe2= 25... gxh2 26. Bxh2 Qg5 26... Bd7 - The Bishop is vulnerable on c8. 27. Nc7 Rb8 28. Ne6 The more annoying 28. Ne8 keeps Black too busy to get anywhere on the Kingside. 28... Rg6 29. Nxd6 Bxd6 30. Rxc8+ Rxc8 31. Rxc8+ Kh7 32. Qd2 28... Bxe6 29. dxe6 Qg6 30. Qd5 Kh7 31. Rg1 Re8 32. Qxa5 Rxe6 33. g3? Now Black's attack builds steam. 33. g4 keeps the Q out of h5. 33... Qh5 34. g4 Qh3 35. Qc3 h5?! What's the rush? 35... Reg6! increases the potency of the ...h5 advance. 36. gxh5 Rg3? An odd end to the game. White now could have escaped by playing ( 36... Rg3 ) 37. Rxg3 fxg3 38. Rg2! and Black doesn't dare take the Bishop, thanks to 39.Qc7+. 0-1 [Ryan/Fritz 9]

Black's King gets mugged.

1. e4 e5 2. f4 exf4 3. Bc4 d5 4. exd5 Qh4+ 5. Kf1 f3 6. Bb5+ c6 6... Bd7 has scored better for Black than the text, in the few book games I found with the 5...f3 line. 7. Nxf3 Qh5 8. Qe2+ Ne7 9. dxc6 bxc6 10. Bc4 Kd8? Frees the Ne7 for immediate action, but the price (loss of castling) is too high. Black needed to continue development. 10... Nd7 and 11...Nb6. 11. Qe5 Nf5 Black braves the attack, but the alternative was 11... Qxe5 12. Nxe5 winning a 2nd pawn. 12. Qa5+ Kd7 13. Ne5+ Ke7 14. Qc7+ Bd7 14... Nd7 does not help much. 15. Nxc6+ Kf6 16. Nc3 adds yet another attacker. If White gets bored of attacking, he can always win some material with Nxa7. 15. Nf3 15. Nxf7 and the threat of Qe5+ is so powerful that Black must shed material to avoid mate. 15... Kf6 16. Nc3 Nd6 17. d3 h6 18. Ne4+ Nxe4 19. dxe4 Qc5 rn3b1r/p1Qb1pp1/2p2k1p/2q5/2B1P3/5N2/PPP3PP/R1B2K1R w - - 0 20 20. Qf4+ It's understandable that a human would eschew 20. b3! with the idea of Bb2+ and Qb7, picking off the a8 Rook, because it looks like the Q has trouble getting back out. However, after 20... Bd6 21. Bb2+ Kg6 22. Qb7 she proves too difficult to trap. For example: 22... Rd8 (22... Qb6 23. Qxa8 Kh7 24. Bd3 Na6 25. e5+ g6 26. Qxh8+ Kxh8 27. exd6+ is similar) 23. Qxa8 Qb6 24. e5 Na6 25. Qxd8 Qxd8 26. exd6 and White gets more than enough material for her. 20... Kg6? At least after 20... Ke7 21. Qxf7+ Kd8 , the King gets a breather. 21. Bxf7+ 21. Qxf7+ Kh7 22. Ng5+ wins the Q. 21... Kh7 22. Ne5 Qe7 23. Bg6+ Kg8 24. Bf7+ Kh7 25. Ng6 Na6 1-0 [Ryan/Fritz 9]

White escapes a positional bind like Houdini out of a straightjacket.

1. d4 Nf6 2. e3 d5 3. Nf3 e6 4. Be2 Be7 5. Nbd2 O-O 6. O-O c5 7. c3 Nc6 8. a3 a6 9. a4 As in Santillan-Guevarra from round 4, Cesar is content to sit back and let his higher-rated opponent dictate play. 9... b6 10. Re1 Qc7 11. h3 Bb7 12. Bd3 Rad8 13. b3 e5 14. dxe5 Nxe5 15. Nxe5 Qxe5 16. Bb2 Ne4 17. Qc2 Nxd2 18. Qxd2 Bd6 18... c4! 19. Bf1 Bd6 keeps wBb2 out of the game a bit longer. 19. f4 Qe7 20. Qf2 20. Qe2 forces a concession like 20... a5 (or 20... Ra8) 20... Qc7 20... c4 21. bxc4 dxc4 22. Bxc4 Bc5 gives pressure against the weak e3 pawn. 21. Qf1 a5 22. Rad1 Rfe8 23. Re2? 23. c4 is needed to stop Black's next. 23... c4! It was bound to be discovered. 24. bxc4 dxc4 25. Bc2 Bc5 26. Rxd8 Qxd8 27. Bc1 Qf6 28. Bd2 Qe6 28... Be4! gets rid of White's best piece. 29. Kh2 f5 30. Qf2 g6 31. Qg3 Kg7 32. h4 Be4 33. Bd1 h6 Unnecessary. 33... Rd8 is more to the point, with the idea of ...Rd6 and ...Qd7, invading on the d-file. 34. Re1 Kf7 35. Kg1 Qd6 36. Qf2 Rg8 36... Rd8 37. Re2 Ba3 38. h5 Bc1! and Black has forced his way in. 37. Bc1 Qf6 38. Bd2 Rd8 39. Be2?! Bd3 39... Rxd2! calls White's bluff. 40. Bxc4+ Bd5 41. Qxd2 Bxc4 and the two powerful Bishops are better than White's Rook and pawn. Queen checks are of no concern, because there are no targets for the wQ to hit. Black, on the other hand, has a wide choice of weak pawns to attack. 40. Kh2 Qe6 Positionally, 40... Bxe2 still makes sense, saddling White with a tall pawn on d2. Tactically, it pays off immediately. 41. Rxe2 Qc6 wins the a-pawn and creates an outside passed pawn, which is sure to give headaches. 41. Bf3 Be4 42. Bd1 Rd5 43. Bc1 Qf6 43... Rd3! 44. Bd2 Qd7 45. Re2 Rd6 46. Qe1 Kg7 ties White's forces in a knot. Black can either play for a slow squeeze with ideas like ...Qd8, ...g5 and ...Ba3-b2(c1), or get down to business and create a passed pawn with ...b5. 44. Bb2 8/5k2/1p3qpp/p1br1p2/P1p1bP1P/2P1P3/1B3QPK/3BR3 b - - 0 44 44... Qd6?? A pity. Aft er building up a dominating position, he traps his own Rook, and gives White the chance he's been waiting for. 44... Qd8 45. Be2 Rd2 46. Bxc4+ Kg7 47. Re2 Rxe2 48. Bxe2 (48. Qxe2 Qxh4+ 49. Kg1 Qxf4 is also won) 48... Qd2 finally puts White out of his misery. 45. Be2 Bd3 A draw offer - if Black wanted to play on, he'd try 45... Rd2 . 46. Bf3 Be4 1/2-1/2 [Ryan/Fritz 9]