The race is tight as three other players are only a point behind.

After Day 3, the fight for first place in the Kortchnoi Zurich Chess Challenge remains tight. Peter Svidler and Hikaru Nakamura are tied for first, each with 7 points, while Vladimir Kramnik, Ian Nepomniachtchi and Viswanathan Anand are only a point back. 

The tournament is using an unusual scoring system: Each win in the portion of the schedule with slower games is worth 2 points and each draw is worth 1 point. On Monday, when the tournament switches to faster time controls, wins will be worth 1 point and draws will be half a point.

The tournament is sponsored chiefly by Oleg Skvortsov and has been rechristened in honor of Viktor Kortchnoi, the legendary grandmaster who died last year

Anand, the former World Champion, entered the third day of play with just one win and a couple of losses. But he mounted a comeback, starting with a vintage strategic win over Grigoriy Oparin.

Anand, V. vs. Oparin, G.
Zurich Korchnoi CC 2017 | Zurich SUI | Round 4 | 15 Apr 2017 | ECO: C95 | 1-0
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Nb8 10. d4 Nbd7 11. Nbd2 Bb7 12. Bc2 Re8 13. Nf1 Bf8 14. Ng3 g6 15. a4 c5 16. d5 c4 17. Bg5 h6 18. Be3 Nc5 19. Qd2 h5 20. Kh1 Qc7 21. Ng5 Bg7 22. Nf1 bxa4? Anand has been playing this position longer than his teenaged opponent has been alive, so the advantage (both objective and subjective) was in White's favor. Yet this is a move Black does not generally want to make. Not only is the pawn on c4 now very weak, but Oparin is unable to prevent Anand from piling up on the a-file.
22... Nfd7 Is among the numerous moves that maintain the status quo.  )
23. Qe2 a5 24. Nd2 Ba6 25. Bxc5 Qxc5 26. Bxa4 Reb8 27. Bc6 Ra7 28. Ra2 Bh6 29. Ngf3 Nd7 30. Bxd7 Rxd7 31. Rea1 Rb5 Trying to keep the c4 pawn might have given Oparin a better opportunity to hold. White would have had to be a bit concerned about the pawn on b2 coming under fire.
31... Bb5  )
32. Qxc4 Qxf2 Material is equal again, but the position is not. Black has too many weak pawns and a lack of harmony among his pieces; his position is in shambles.
33. Qc6 Ra7 34. b4
34. Qxd6 Was simple enough.
34... Bxd2 Is met by
35. b4  )
34... Bxd2 35. Nxd2 Qe3 36. Nc4 Qxe4 37. Nxd6 Qxd5 38. Qxd5 Rxd5 39. Ne4 White wins by a tempo. If not for the threat of Nf6+, Black could move his bishop away and avoid the pin.
39... Kg7 40. Rxa5 Bd3 41. Rxa7 Bxe4 42. Re1

In the same round, Nepomniachtchi broke open the position for his two bishops to eviscerate Boris Gelfand’s kingside. Gelfand had been playing extremely solidly prior to this game, recording three consecutive draws. Nepomniachtchi’s win allowed him to take over sole possession of first after Round 4. 

Nepomniachtchi, Ian vs. Gelfand, Boris
Korchnoi Zurich Chess Challenge | ? | Round 4.4 | 15 Apr 2017 | ECO: B92 | 1-0
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e5 7. Nb3 Be7 8. O-O O-O 9. Qd3 Be6 10. Bd2 Nbd7 11. Nd5 Bxd5 12. exd5 Nc5?! I'm not a big fan of this move. Gelfand naturally wanted to remove his knight from f6 and play f7-f5 (and potentially Bg5, to create a situation of knight versus light-squared bishop). But Nepomniachtchi now has a connected passed pawn. Thus, White can do as he likes, without risk, in an attempt to make progress.
12... Qc8 Defends the c5 square with a piece, and also allows the bishop to switch to the queenside via d8. This certainly was a superior option.  )
13. Nxc5 dxc5 14. c4 Qc7 15. Rae1 Bd6 16. Qh3 This is a nice move. While it appears to have no concrete threat, White can now place his bishops on their best diagonals.
16... Rfe8 17. Bc3 g6
17... b5 Was probably necessary. Black needs to find counterplay and in the game he did not create any.  )
18. Bd3 Nh5 19. g3 Re7 20. Re2 Rf8 21. Rfe1 f5 Gelfand has gained space, but it came at a cost. As pawns push forward, they leave behind many weaknesses. Nepomniachtchi effectively exploits them.
22. f3 Nf6 23. Qh4 Nd7 24. Qg5 Ref7
24... b5 Gelfand was reluctant to do anything on the queenside, but he needed to try something. It is not clear how White is going to break through, so closing down the queenside with
25. b3 b4 was a possibility. Gelfand would be forced to sit and wait, hoping Nepomniachtchi could not find a win.  )
25. Qd2 Qd8 26. Kh1 Re8 27. a4 There's no rush on the kingside, so White closes the queenside before pushing forward.
27... h5? Black's position was already bad, but this hastens his fall.
28. a5 White could have won more rapidly after:
28. g4! hxg4 29. fxg4 e4 30. gxf5 The bishop on d3 is immune as the e-pawn is pinned, and the exposed kingside is beyond repair. The impending move Qh6 is deadly.  )
28... Kh7 29. Bc2 The threat is to reroute the bishop to a4 to undermine the pawn on e5. The move also removes the bishop as a potential target should Gelfand play e4, making g3-g4 more effective.
29. g4 hxg4 30. fxg4 Qh4 Would have given Gelfand counterplay.  )
29... b5 Far too late, the position is already beyond salvage.
30. axb6 Nxb6 31. Qd3 Qb8 32. g4 Nd7 Capturing on g4 is no better because the queen has access to h3.
32... hxg4 33. fxg4 e4 34. Qh3+ Kg8 35. Qh8#  )
33. gxf5 gxf5 34. f4 e4 35. Qh3 Kh6 36. Rg2 Bxf4 37. Bd1 Gelfand resigned, as mate is unstoppable.

Yannick Pelletier, the local Swiss grandmaster and lowest rated player in the field, was never in any danger against Svidler in Round 4 and held comfortably with the Black pieces. In the final game of the round, and the longest of the tournament so far, Nakamura and Kramnik had a 63-move dual that ended with perpetual check. Nakamura demonstrated exceptional defense to hold the balance against Kramnik, another former World Champion.

Nepomniachtchi’s time at the top of the leaderboard was short-lived. In Round 5, he faced Nakamura in a highly anticipated game, which did not disappoint.

Nakamura, who is a more dangerous opponent as the time controls gets shorter, controlled the game from start to finish, first separating Nepomniachtchi’s queenside pawns and then exploiting weaknesses on both sides of the board.

Nakamura, Hikaru vs. Nepomniachtchi, Ian
Zurich Korchnoi CC 2017 | Zurich SUI | Round 5 | 15 Apr 2017 | ECO: D94 | 1-0
1. d4 It's rare to see a grandmaster as strong as Nepomniachtchi get dominated from start to finish. Yet this game clearly suited Nakamura's style, and Nepomniachtchi was unable to withstand the pressure.
1... Nf6 2. Nf3 g6 3. e3 Bg7 4. c4 O-O 5. Be2 b6 6. O-O Bb7 7. Nc3 d5 8. cxd5 Nxd5 9. Bd2 Nd7 10. Nxd5 Bxd5 11. Bc3 c5 12. Rc1 e6 13. Qa4 a6 14. Qa3 The opening has worked out in White's favor. He has long-lasting queenside pressure because Black's pawns are vulnerable. The game continuation is very pleasant for White, with no risk and easy play.
14... Qb8 15. dxc5 Bxc3 16. Qxc3 bxc5
16... Rc8 Does not restore full equality, but it attempts to keep the pawn structure intact. White's position is clearly preferable, but there is a long way to go before he can win.  )
17. Nd2 a5 18. a4! The move looks like it might weaken the b-file, but really it secures the queenside for Nakamura. The b5 square is now supported for a bishop entry, and the c4 square will be controlled by b2-b3.
18... Qb7 19. e4 Bc6
19... Bxe4 20. Nxe4 Qxe4 21. Bf3 Qxa4 22. Bxa8 Rxa8 Is desperate, but perhaps defensible. Black would have two pawns for the exchange and White would still have much work to do.  )
20. b3 Rfb8 21. Qe3 Qc7 22. Rfd1 Rb4 23. Nc4 Rab8 24. Rc3 Nf6 25. f3 Black has no activity, leaving Nepomniachtchi with the extremely unpleasant task of trying to hold without any counterplay.
25... Nd7 26. Qd2 Nb6 27. Qg5 Nxc4 28. Bxc4 e5 A really sad move to have to play, but Black was in danger of being mated if White had the opportunity to play Rd3-d8 and e4-e5. Not to mention, the pawn on c5 was en prise.
29. h4! Nakamura knows how to handle these positions. He forces his opponent to create another weakness, or else get mated.
29... Kg7 30. h5 h6 31. Qe3 Rd8
31... gxh5 32. Rcd3 And Black could resign as he cannot stop the White rook from going to d6.
32... Bxa4 33. Rd6 Rh8 34. Qc3 And Black's position collapses.  )
32. Rxd8 Qxd8 33. hxg6 fxg6 34. Qxc5 Qb6
34... Qd4+ 35. Qxd4 exd4 36. Rc1 Not
...   )
35. Bb5! Nepomniachtchi resigned because he is losing more material. If the queens are exchanged, Nakamura would win at least one more pawn.

Gelfand, who faced Anand, sacrificed a pawn early to prevent his opponent from castling and to obtain the two bishops. Yet, even when Gelfand equalized material, he faced problems as Anand’s central pawns moved forward en masse, with his king just behind in support. In the end, both of Anand’s rooks invaded Gelfand’s second rank and Gelfand resigned as he faced checkmate.

Boris Gelfand vs. Viswanathan Anand
Korchnoi Zurich Chess Challenge | Zurich SUI | Round 5 | 15 Apr 2017 | ECO: A37 | 0-1
1. c4 c5 2. g3 g6 3. Bg2 Bg7 4. Nc3 Nc6 5. Nf3 e6 6. d4 Nxd4 7. Bf4 Ne7 8. Nxd4 cxd4 9. Nb5 e5 10. Nd6+ Kf8 11. Bd2 Qb6 12. Nxc8 Rxc8 13. Qb3 f5 14. Bxb7 Rc7 15. Bg2 e4 16. O-O Kf7 17. Rfc1 Rhc8 18. Bf4 Qxb3 19. axb3 Rb7 20. Bd6 Ke6 21. c5 Rxb3 22. Rxa7 Nc6 23. Ra2 Be5 24. Bxe5 Kxe5 25. f3 d3 26. exd3 Nb4 27. d4+ Kxd4 28. Ra7 d5 29. fxe4 fxe4 30. Rd1+ Rd3 31. Rda1 Rxc5 32. Bf1 Rd2 33. Rxh7 Nd3 34. b4 Rcc2 35. b5 Ne5 36. Ra4+ Kc5

Pelletier, who had White against Kramnik, earned his third straight draw. Svidler, a seven-time champion of Russia, defeated Oparin, his young compatriot. That game saw pieces flying across the board early, but when the smoke cleared Svidler had a winning ending. The victory catapulted him back into a lead for first.

Grigoriy Oparin vs. Peter Svidler
Korchnoi Zurich Chess Challenge | Zurich SUI | Round 5 | 15 Apr 2017 | ECO: B90 | 0-1
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. h4 e5 7. Nb3 Be6 8. f4 g6 9. Be2 Nbd7 10. g4 h5 11. g5 Ng4 12. Rf1 exf4 13. Bxf4 Nde5 14. Qd2 Qc7 15. O-O-O Rd8 16. Nd5 Bxd5 17. Qxd5 Bg7 18. Nd4 O-O 19. Kb1 Rfe8 20. c3 Rc8 21. Bxg4 hxg4 22. h5 gxh5 23. Nf5 Re6 24. Rh1 Ng6 25. Bg3 Qb6 26. Nxg7 Kxg7 27. Rxh5 Qe3 28. Bxd6 Qxe4+ 29. Qxe4 Rxe4 30. Rhh1 Nf4 31. Rdf1 Nh3 32. Rf5 Rc6 33. Rd1 Re6 34. Bg3 Kg6 35. Rff1 Re3 36. Bb8 Rf3 37. Rxf3 gxf3 38. Rf1 f2 39. Bg3 Rc5 40. Kc2 Rxg5

Sunday will wrap up the slow portion of the tournament.

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Robert Hess is a former United States Junior Champion, recipient of the 2010 Samford Award (the most prestigious in the United States for young players) and was runner-up in the 2009 United States Championships. A 2015 graduate of Yale University, he is the chief operating officer of The Sports Quotient, a statistically-based sports site that he co-founded. He can be found on Twitter at @GM_Hess.