[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2009.06.30"]
[Round "7"]
[White "Van Os, Albert"]
[Black "Aalders, Peter"]
[Result "0-1"]
[ECO "C86"]
[WhiteElo "1875"]
[BlackElo "1804"]
[PlyCount "108"]
[EventDate "2009.05.19"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. Qe2 b5 6. Bb3 Be7 7. c3 0-0 8. 0-0 d6 9. h3 Na5 10. Bc2 c5 11. d4 Qc7 12. d5 c4 13. Be3 Bd7 14. Nbd2 Nb7 15. a4 Nc5 16. Rfc1 Nxa4 17. Bxa4 bxa4 18. Qxc4 Rfc8 19. Qd3 Rab8 20. Rc2 Be8 21. Qe2 Rb7 22. Ne1 Qb8 23. Nd3 a5 24. c4 Rbc7 25. f4 exf4 26. Bxf4 Nd7 27. Kh2 f6 28. Rac1 Ne5 29. Be3 Nxd3 30. Qxd3 Qb4 31. Bd4 Bg6 32. Bc3 Qb6 33. Bd4 Qb4 34. Bc3 Qb6 35. Ra1 Be8 36. Qg3 Qa6 37. Rcc1 Kh8 38. Rf1 Bf8 39. e5 dxe5 40. Bxe5 Rf7 41. Bf4 g5 42. Bxg5 fxg5 43. Qxg5 Qd6+ 44. Kh1 Rg7 45. Qf4 Bg6 46. Qxd6 Bxd6 47. Rxa4 Bb4 48. Nf3 Rxc4 49. Raa1 Be4 50. Rad1 Bd6 51. Rd2 Rf7 52. Rdd1 Rc2 53. b3 Rg7 54. Rg1 Bxf3 0-1

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2009.06.23"]
[Round "6"]
[White "Van Ketel, Raoul"]
[Black "Van Os, Albert"]
[Result "1-0"]
[ECO "A80"]
[WhiteElo "2244"]
[BlackElo "1875"]
[PlyCount "43"]
[EventDate "2009.05.19"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. d4 f5 2. Bg5 h6 3. Bh4 g5 4. e3 Nf6 5. Bg3 d6 6. h4 g4 7. h5 c6 8. Nc3 Be6 9. Nge2 Bf7 10. Nf4 Rg8 11. Be2 Nbd7 12. Qd3 e5 13. dxe5 dxe5 14. Ng6 e4 15. Qd2 Bb4 16. a3 Bxc3 17. Qxc3 Nd5 18. Qd4 c5 19. Qd2 Qb6 20. 0-0-0 0-0-0 21. Qxd5 Bxd5 22. Ne7# 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2009.06.09"]
[Round "4"]
[White "Jansen, Norbert"]
[Black "Van Os, Albert"]
[Result "1-0"]
[ECO "B37"]
[WhiteElo "2124"]
[BlackElo "1875"]
[PlyCount "101"]
[EventDate "2009.05.19"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. c4 d6 6. Nc2 Nf6 7. Nc3 Bg7 8. Be2 Be6 9. 0-0 0-0 10. Be3 Ne5 11. b3 Nc6 12. Nd4 Bd7 13. Qd2 Qa5 14. Rfd1 Rfe8 15. f3 a6 16. a3 Ne5 17. b4 Qc7 18. Rac1 Rec8 19. Nd5 Qd8 20. h3 Bc6 21. Bh6 Bh8 22. Bg5 Bxd5 23. cxd5 Rxc1 24. Rxc1 Rc8 25. Be3 Ned7 26. Nb3 Rc7 27. Na5 Qc8 28. Kf2 Bg7 29. Ke1 h5 30. Kd1 Ne8 31. Rxc7 Nxc7 32. Bd4 f6 33. Qc3 Kf7 34. Kc2 Ke8 35. Kb3 Qb8 36. a4 b5 37. Nc6 bxa4+ 38. Kxa4 Qb7 39. Na5 Qb8 40. Qc6 Kd8 41. Bxa6 Bh6 42. Nb7+ Ke8 43. b5 Bf4 44. Bb6 Na8 45. Bf2 Nc7 46. Na5 Kd8 47. Nc4 f5 48. Bb7 fxe4 49. fxe4 Nf6 50. e5 Ncxd5 51. exf6 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2009.06.02"]
[Round "3"]
[White "Van Os, Albert"]
[Black "Otto, Paul"]
[Result "1-0"]
[ECO "B10"]
[WhiteElo "1875"]
[BlackElo "1277"]
[PlyCount "63"]
[EventDate "2009.05.19"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c6 2. Nf3 d5 3. exd5 cxd5 4. Ne5 Nf6 5. d4 Nc6 6. Bb5 Qb6 7. Nc3 e6 8. 0-0 Be7 9. a4 a5 10. Be3 0-0 11. Kh1 Nd7 12. Ne2 Qc7 13. f4 f6 14. Nf3 Bd6 15. c3 Rd8 16. Bd3 e5 17. fxe5 fxe5 18. dxe5 Ndxe5 19. Ng5 g6 20. Nd4 Nxd4 21. Bxd4 Nxd3 22. Qxd3 Bf5 23. Rxf5 gxf5 24. Qxf5 Re8 25. Qxd5+ Kf8 26. Rf1+ Ke7 27. Rf7+ Kd8 28. Ne6+ Kc8 29. Nxc7 Re1+ 30. Bg1 Bxc7 31. Qd7+ Kb8 32. Qxc7# 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2009.05.19"]
[Round "1"]
[White "Van Os, Albert"]
[Black "Van Haastert, Edwin"]
[Result "0-1"]
[ECO "C03"]
[WhiteElo "1875"]
[BlackElo "2389"]
[PlyCount "88"]
[EventDate "2009.05.19"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 e6 2. d4 d5 3. Nd2 Be7 4. f4 c5 5. c3 cxd4 6. cxd4 dxe4 7. Nxe4 Nf6 8. Bd3 0-0 9. Nf3 Nc6 10. Be3 Qa5+ 11. Bd2 Qb6 12. Bc3 Nb4 13. 0-0 Nxd3 14. Qxd3 Bd7 15. a4 Nxe4 16. Qxe4 Bc6 17. Qc2 Bxf3 18. Rxf3 Bf6 19. Qe4 Rfd8 20. Rd3 Rd5 21. a5 Qb5 22. g4 g6 23. Rad1 Rad8 24. R3d2 Be7 25. Rg2 Bb4 26. Ra1 Rc8 27. f5 Bxc3 28. bxc3 exf5 29. gxf5 Rxf5 30. a6 bxa6 31. Rb1 Qa5 32. h4 Rb5 33. Rf1 Qxc3 34. Qf4 Rb7 35. h5 Rd7 36. Rg4 Re8 37. hxg6 hxg6 38. Rf3 Qe1+ 39. Kh2 Re2+ 40. Rg2 Rxg2+ 41. Kxg2 Qe2+ 42. Rf2 Qe6 43. Rb2 Qd5+ 44. Kg3 Qxd4 0-1

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.07.01"]
[Round "7"]
[White "Jonk, Geert Jan"]
[Black "Van Os, Albert"]
[Result "1/2-1/2"]
[ECO "B23"]
[WhiteElo "1856"]
[BlackElo "1842"]
[PlyCount "101"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nc3 a6 3. g3 b5 4. Bg2 Bb7 5. d3 e6 6. Nh3 b4 7. Ne2 d5 8. 0-0 Be7 9. e5 h5 10. Nef4 g6 11. c4 bxc3 12. bxc3 Qc7 13. Rb1 Bc6 14. c4 d4 15. Nd5 Qd8 16. Nxe7 Nxe7 17. Bg5 Qc7 18. Bf6 Rg8 19. Bxe7 Kxe7 20. Re1 Nd7 21. Bxc6 Qxc6 22. Qd2 Rgb8 23. Qg5+ Ke8 24. Qf4 Rxb1 25. Rxb1 Rb8 26. Re1 Ke7 27. Ng5 Rf8 28. Ne4 Kd8 29. Rb1 Kc7 30. Nd6 f6 31. exf6 e5 32. Qe4 Kxd6 33. Qxg6 Rxf6 34. Qxh5 e4 35. dxe4 Qxe4 36. Rf1 Ne5 37. f4 Nxc4 38. Qh8 Ke7 39. Qg7+ Rf7 40. Qg5+ Kd6 41. Qh6+ Qe6 42. Qh8 Qe3+ 43. Kg2 Qe2+ 44. Kg1 Kc7 45. Qa8 Qe3+ 46. Kg2 Re7 47. Qa7+ Kd6 48. Qxa6+ Kd5 49. Qa8+ Kd6 50. Qa6+ Kd5 51. Qa8+ 1/2-1/2

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.06.24"]
[Round "6"]
[White "Van Os, Albert"]
[Black "Van Gunsteren, Duleen"]
[Result "1-0"]
[ECO "B51"]
[WhiteElo "1842"]
[PlyCount "42"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. Bb5 d6 4. Bxc6+ bxc6 5. 0-0 e5 6. d3 Be7 7. Nbd2 Nf6 8. Re1 0-0 9. Nc4 Nd7 10. Bd2 Nb6 11. Ba5 Ba6 12. Ne3 Qd7 13. Nf5 Bd8 14. Bd2 g6 15. Nh6+ Kg7 16. Ng5 Bxg5 17. Bxg5 f6 18. Bd2 Bc8 19. h3 c4 20. Ng4 h5 21. Bh6+ Kh7 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.06.17"]
[Round "5"]
[White "Termeulen, Albert"]
[Black "Van Os, Albert"]
[Result "1-0"]
[ECO "B34"]
[WhiteElo "2087"]
[BlackElo "1842"]
[PlyCount "57"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nc3 a6 3. Nf3 Nc6 4. d4 cxd4 5. Nxd4 g6 6. Bc4 Bg7 7. Be3 Qa5 8. Bb3 Nf6 9. f3 0-0 10. Qd2 Rd8 11. 0-0-0 Ne5 12. h3 b5 13. f4 Nc4 14. Bxc4 bxc4 15. Nc6 Nxe4 16. Nxa5 Nxd2 17. Rxd2 Bxc3 18. bxc3 Re8 19. Nxc4 d6 20. Nb6 Rb8 21. a4 Rb7 22. a5 Be6 23. g4 Rc7 24. Kb2 f5 25. Rg1 Kf7 26. Rd4 Rc5 27. Ra4 Rc6 28. c4 Rb8 29. Kc3 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.06.10"]
[Round "4"]
[White "Van Os, Albert"]
[Black "Schenkelaars, Vincent"]
[Result "1-0"]
[ECO "B07"]
[WhiteElo "1842"]
[BlackElo "1835"]
[PlyCount "57"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Be2 Bg7 5. h4 c5 6. Nf3 Bg4 7. Be3 Qa5 8. 0-0 0-0 9. d5 b5 10. Nd2 Bxe2 11. Qxe2 a6 12. Nd1 Nbd7 13. f4 h5 14. Nf2 e6 15. dxe6 fxe6 16. c3 Qd8 17. Nf3 Qe7 18. Ng5 Bh6 19. Rad1 Rad8 20. Qd3 Bxg5 21. hxg5 Ne8 22. e5 d5 23. Qxg6+ Ng7 24. g4 h4 25. Kg2 Rf7 26. Rh1 Nf8 27. Qc2 d4 28. Bc1 Qb7+ 29. Qe4 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.06.03"]
[Round "3"]
[White "Agaian, Jura"]
[Black "Van Os, Albert"]
[Result "1-0"]
[ECO "B34"]
[WhiteElo "1840"]
[BlackElo "1842"]
[PlyCount "77"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6 6. Be3 Bg7 7. Qd2 Ng4 8. Nxc6 bxc6 9. Bd4 e5 10. Bc5 Qf6 11. f3 Nh6 12. Bc4 Ng8 13. 0-0 Ne7 14. Rad1 g5 15. Ba6 d5 16. Bxc8 Rxc8 17. exd5 cxd5 18. b4 Qf4 19. Qf2 Qc4 20. Rd3 Rd8 21. a4 f5 22. Qd2 Bf6 23. Bxe7 Bxe7 24. Nxd5 h6 25. Rd1 Kf7 26. Qe1 Rd6 27. c3 Rb8 28. Ne3 Qxd3 29. Rxd3 Rxd3 30. Nxf5 Kf6 31. Qe4 Rxc3 32. Ne3 Rc1+ 33. Kf2 Re8 34. Qh7 h5 35. Qxh5 Rd8 36. Qh6+ Kf7 37. Qh7+ Ke8 38. Qg6+ Kd7 39. Nd5 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.05.27"]
[Round "2"]
[White "Van Os, Albert"]
[Black "Van Gunsteren, Lex"]
[Result "1-0"]
[ECO "B30"]
[WhiteElo "1842"]
[BlackElo "1642"]
[PlyCount "63"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. Bb5 Nf6 4. e5 Nd5 5. c4 Nc7 6. Ba4 a6 7. Nc3 g6 8. 0-0 Bg7 9. Re1 0-0 10. d3 Nd4 11. Nxd4 cxd4 12. Nd5 b5 13. Bb3 Rb8 14. Bg5 Nxd5 15. cxd5 d6 16. exd6 Qd7 17. dxe7 Re8 18. Qf3 Qf5 19. Qxf5 Bxf5 20. d6 Rb7 21. Bd5 Rb6 22. Bf4 g5 23. Bg3 h5 24. h3 Bd7 25. Rac1 g4 26. hxg4 Bxg4 27. Rc7 h4 28. Bf4 Bf6 29. Bc6 Rxc6 30. Rxc6 Bf5 31. Rc7 Bxd3 32. d7 1-0

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2008.05.20"]
[Round "1"]
[White "Van Vliet, Jeffrey"]
[Black "Van Os, Albert"]
[Result "1-0"]
[ECO "B35"]
[WhiteElo "2285"]
[BlackElo "1842"]
[PlyCount "77"]
[EventDate "2008.05.20"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. Nc3 g6 4. d4 cxd4 5. Nxd4 Bg7 6. Be3 Nf6 7. Bc4 0-0 8. Bb3 Qa5 9. f3 d5 10. exd5 Nb4 11. Qd2 Nbxd5 12. Nxd5 Qxd2+ 13. Bxd2 Nxd5 14. Nb5 Rd8 15. 0-0-0 Be6 16. Bxd5 Bxd5 17. Ba5 b6 18. Nc7 Bxa2 19. Nxa8 Rxa8 20. Bd2 Rc8 21. Be3 f5 22. Rd7 Bb3 23. Rd2 Ba4 24. Kb1 e5 25. Rhd1 Rc7 26. b3 Bc6 27. Rd6 f4 28. Bc1 a5 29. Re1 a4 30. Bb2 axb3 31. cxb3 Bf8 32. Rd8 Kf7 33. Bxe5 Ra7 34. Rc8 Bd5 35. Kb2 Ba3+ 36. Kc2 Ra5 37. Rc7+ Kg8 38. Bc3 Rc5 39. Re8# 1-0

[Event "NED-chT 0708"]
[Site "Netherlands"]
[Date "2007.11.03"]
[Round "3.6"]
[White "Van Os, Albert"]
[Black "Okkes, Menno"]
[Result "0-1"]
[ECO "B15"]
[BlackElo "2386"]
[PlyCount "92"]
[EventDate "2007.09.15"]
[EventType "team-tourn"]
[EventRounds "9"]
[EventCountry "NED"]
[SourceTitle "EXT 2008"]
[Source "ChessBase"]
[SourceDate "2007.11.25"]
[SourceVersion "1"]
[SourceVersionDate "2007.11.25"]
[SourceQuality "1"]
[WhiteTeam "Leiden LSG II"]
[BlackTeam "Enschede ESGOO"]
[WhiteTeamCountry "NED"]
[BlackTeamCountry "NED"]

1. e4 c6 2. Nf3 d5 3. exd5 cxd5 4. Ne5 Nc6 5. d4 g6 6. Bb5 Bd7 7. Nxd7 Qxd7 8. Nc3 Bg7 9. Be3 Nf6 10. h3 0-0 11. 0-0 a6 12. Ba4 b5 13. Bb3 Na5 14. Qf3 e6 15. Bg5 Ne8 16. Rfd1 Rc8 17. Ne2 Nd6 18. c3 Nac4 19. Rab1 a5 20. Bc2 b4 21. Bf6 bxc3 22. bxc3 Na3 23. Rbc1 Rb8 24. Bxg7 Kxg7 25. Nf4 Rb2 26. Bb3 a4 27. Nd3 Rxb3 28. axb3 axb3 29. Qe2 Ndc4 30. Nc5 Qb5 31. Nxb3 Qxb3 32. h4 h5 33. g4 Rh8 34. g5 Qb7 35. Qf3 Qe7 36. Re1 Rd8 37. Re2 Rd7 38. Ra1 Rb7 39. Qf4 Qd8 40. Rea2 Rb3 41. Qc1 Qb8 42. Kg2 Qd6 43. f4 Nb5 44. Ra6 Rxc3 45. Rxd6 Rxc1 46. Rxc1 Ncxd6 0-1

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2007.06.26"]
[Round "7"]
[White "Van Os, Albert"]
[Black "Zwinkels, Wim"]
[Result "1/2-1/2"]
[ECO "B90"]
[WhiteElo "1880"]
[BlackElo "1878"]
[PlyCount "67"]
[EventDate "2007.05.15"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nf3 h6 8. Bc4 Be6 9. Bxe6 fxe6 10. a4 b6 11. Qd2 Nc6 12. Rd1 Ng4 13. 0-0 Be7 14. Qe2 Nxe3 15. Qxe3 0-0 16. Rd2 Bf6 17. Ne2 Rc8 18. Rfd1 Nd4 19. Nexd4 exd4 20. Qb3 d5 21. e5 Bg5 22. Rxd4 Qc7 23. Rb4 Bd8 24. Rd2 Rf5 25. Re2 Qf7 26. Qd3 a5 27. Rd4 Bc7 28. c4 dxc4 29. Rxc4 Rf8 30. Rd4 Bxe5 31. Nxe5 Rxe5 32. f3 Rc5 33. Rd7 Rc1+ 34. Kf2 1/2-1/2

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2007.06.19"]
[Round "6"]
[White "De Waard, Ad"]
[Black "Van Os, Albert"]
[Result "0-1"]
[ECO "B22"]
[WhiteElo "1411"]
[BlackElo "1880"]
[PlyCount "68"]
[EventDate "2007.05.15"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. c3 d5 3. exd5 Qxd5 4. d4 e6 5. Nf3 Nc6 6. Bd3 Nf6 7. 0-0 Bd7 8. Bc2 0-0-0 9. Bb3 c4 10. Bc2 h6 11. b3 b5 12. a4 a6 13. axb5 axb5 14. bxc4 bxc4 15. Qe2 Bd6 16. Na3 Na5 17. Re1 Bc6 18. Nxc4 Nxc4 19. Bb3 Bxh2+ 20. Kh1 Bc7 21. Bxc4 Qh5+ 22. Kg1 Ng4 23. Bxe6+ fxe6 24. Qxe6+ Kb7 25. Rb1+ Bb5 26. c4 Rhe8 27. Rxb5+ Qxb5 28. cxb5 Rxe6 29. Rxe6 Rd7 30. Be3 Nf6 31. Ne5 Rd5 32. Nc6 Rxb5 33. Ne5 Ng4 34. Rg6 Rb1+ 0-1

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2007.06.12"]
[Round "5"]
[White "Van Os, Albert"]
[Black "Spaans, Coenraad"]
[Result "0-1"]
[ECO "B31"]
[WhiteElo "1880"]
[BlackElo "1987"]
[PlyCount "84"]
[EventDate "2007.05.15"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nf3 Nc6 3. Bb5 g6 4. 0-0 Bg7 5. Bxc6 bxc6 6. d3 d6 7. Nc3 Nf6 8. Bd2 0-0 9. Rb1 Nd7 10. Ne2 Rb8 11. Qc1 Re8 12. Ng3 Nf8 13. h4 e5 14. h5 Bg4 15. hxg6 hxg6 16. Nh2 Be6 17. b3 Nh7 18. Nf3 f5 19. exf5 gxf5 20. Nh5 f4 21. Nxg7 Kxg7 22. Bc3 Qf6 23. Re1 Bd5 24. Nd2 Ng5 25. Ne4 Bxe4 26. dxe4 Qg6 27. Kf1 Nxe4 28. Bb2 Qf5 29. f3 Ng3+ 30. Kf2 Qg5 31. Qd2 Nf5 32. Rh1 Qg3+ 33. Kg1 Re6 34. Rh3 Qg5 35. Kh2 Rh8 36. Rg1 Qg3+ 37. Kh1 Reh6 38. Bxe5+ dxe5 39. Qd7+ Kf6 40. Qxc6+ Kg5 41. Qxh6+ Rxh6 42. Rxh6 Kxh6 0-1

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2007.06.05"]
[Round "4"]
[White "Van de Peut, Aart A"]
[Black "Van Os, Albert"]
[Result "1/2-1/2"]
[ECO "B25"]
[WhiteElo "1924"]
[BlackElo "1880"]
[PlyCount "46"]
[EventDate "2007.05.15"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 c5 2. Nc3 d6 3. g3 Nc6 4. Bg2 g6 5. d3 Bg7 6. f4 e6 7. Nf3 Nge7 8. 0-0 0-0 9. Be3 b6 10. Qd2 Bb7 11. Rae1 d5 12. exd5 Nxd5 13. Nxd5 exd5 14. f5 f6 15. fxg6 hxg6 16. Bh6 Qd7 17. Nh4 Kh7 18. Bxg7 Kxg7 19. c3 d4 20. Be4 Ne5 21. Qg2 Rab8 22. Qe2 dxc3 23. bxc3 Bxe4 1/2-1/2

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2007.05.29"]
[Round "3"]
[White "Van Os, Albert"]
[Black "Bakker, Joop"]
[Result "1/2-1/2"]
[ECO "C41"]
[WhiteElo "1880"]
[BlackElo "1927"]
[PlyCount "63"]
[EventDate "2007.05.15"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. e4 e5 2. Nf3 d6 3. d4 exd4 4. Nxd4 Nf6 5. Nc3 Be7 6. Be2 0-0 7. 0-0 Re8 8. Bf3 Nbd7 9. Bf4 Ne5 10. Bxe5 dxe5 11. Ndb5 c6 12. Na3 Bxa3 13. bxa3 Qa5 14. Nb1 Rd8 15. Qc1 Be6 16. c3 Rd3 17. Qb2 Qb6 18. Qc2 Rad8 19. Be2 R3d6 20. c4 Qa5 21. f3 Qc5+ 22. Kh1 Qe3 23. c5 Rd2 24. Nxd2 Rxd2 25. Rfd1 Rd4 26. Rxd4 exd4 27. Rd1 Nd7 28. Qb2 Nxc5 29. Qxd4 Qxd4 30. Rxd4 Kf8 31. Bc4 Ke7 32. Kg1 1/2-1/2

[Event "Leiden SB-ch"]
[Site "Leiden"]
[Date "2007.05.22"]
[Round "2"]
[White "Oosterom, Erik"]
[Black "Van Os, Albert"]
[Result "1-0"]
[ECO "A87"]
[WhiteElo "2062"]
[BlackElo "1880"]
[PlyCount "58"]
[EventDate "2007.05.15"]
[EventType "swiss"]
[EventRounds "7"]
[EventCountry "NED"]
[SourceTitle "EXT 2012"]
[Source "ChessBase"]
[SourceDate "2011.11.24"]
[SourceVersion "1"]
[SourceVersionDate "2011.11.24"]
[SourceQuality "1"]

1. d4 f5 2. g3 Nf6 3. Bg2 g6 4. Nf3 Bg7 5. c4 0-0 6. 0-0 d6 7. Nc3 Qe8 8. Nd5 Na6 9. Nxf6+ Bxf6 10. Bh6 Bg7 11. Qd2 c6 12. Rfe1 Qf7 13. Bxg7 Qxg7 14. e4 Nc7 15. d5 cxd5 16. exd5 Bd7 17. Qd4 Rf6 18. Rac1 b6 19. b4 Re8 20. c5 Nb5 21. Qd3 dxc5 22. bxc5 bxc5 23. Rxc5 a6 24. Ne5 Bc8 25. Rec1 Rff8 26. Nc6 e5 27. dxe6 Bxe6 28. a4 Nc7 29. Ne5 Rd8 1-0

