Nakamura tried the King's Indian again and held Ponomariov to a draw without too many problems. Robson and Finegold certainly gave fans their money's worth with a 137-move clash which tested the endgame skills and endurance of both!
So Nakamura and Ponomariov remain all-square and Robson still leads Finegold thanks to his opening day victory.
The sixth and final game at standard time controls takes place on Sunday, after which the players have a break on Monday before completing the matches with four rapid games (two each day on Monday and Tuesday).
UPDATE: OFFICIAL NEWS REPORT
Draws Abound in Rounds 4 and 5 in Saint Louis
By Ken West
The world did not end Saturday, even though Grandmaster Hikaru Nakamura again played the King's Indian Defense against GM Ruslan Ponomariov, and the fifth game in the international match ended in a draw.
Their match is tied at 2.5 each.
The game between GM Ben Finegold and GM Ray Robson went a epic 137 moves, with Finegold pressing for his first win. He had two pawns, on the f and g files, and a knight against Robson's dark squared bishop and g pawn. The latter part of the game focused on Finegold trying to get his king to f5 in attempt to gain Robsons pawn on g5. But Robson's king kept his opponent's king from the square.
The game ended in a draw after no captures were made under the 50-move rule. Robson leads their match 3-2.
The games are going on at the Chess Club and Scholastic Center of Saint Louis through May 25.
For the second game in the match, Nakamura played Na6 on his seventh move, the same move in his game three win. However, after Ponomariov again played Bg5 on move 10, Nakamura played Qc7 instead of the f6 he played in game three. Even though Nakamura won game three, he said his opening was worse in that game.
International Master John Donaldson, providing commentary on the match with WGM Jen Shahade, said the placement of the Queen on c7 is atypical.
"Its kind of an odd place to have the queen", Donaldson said.
Nakamura proved steadfast in his belief of the Kings Indian defense.
Its playable, Nakamura said after the game about the Kings Indian even though he said has had to play against the former world champion in worse positions.
Everyone plays multiple openings, Nakamura said. Whether I play it again in matches, well see.
Nakamura said he was still in preparation on move 17 and said his position should have been fine. However he thought a5 on his 19th move was not accurate.
I simply forgot after Qd4, Qc7, I lose immediately to e5, he said.
Instead, Nakamura opted to place his rook on d7 instead of making the losing queen move.
The Saint Louis grandmaster said Ponomariov's knight transfer from e1 to f2 on move 27 was stronger than he first thought. But, he felt the former world champions Kg2 on move 32 was a mistake. He thought Ponomariov could have played his rook to e1, heading to the h file.
Rh1 seems very unpleasant for me, Nakamura said. After Kg2, it goes to where I am much worse to where I have crazy notions I might win.
However, he said his Rg7 lost a tempo and h5 was desperation.
My position was slowly, slowly improving, and I had some hope, Ponomariov said. But he calculated some variations better than me.
Finegold said after his game with Robson that he was winning in the late-middle game until he hung a pawn. Shortly after that, Robson also dropped a pawn. Neither could remember having one of their games drawn by the 50-move rule.
Round four also featured draws in both games.
Nakamura's opening choice in his fourth game Friday against Pomarianov surprised Shahade.
This is not Naka chess, she said in her commentary after Nakamura played d4 in the opening and took blacks pawn with his fourth move, cxd4.
That game ended in a draw as did the other match between GMs Robson and Finegold.
Donaldson agreed with Shahade about Nakamura's opening.
I don't know any games Hikaru has played the white side of the Queen's Gambit Declined exchange, he said.
After the game Nakamura said the ideas are pretty straightforward in the line he chose. But then Ponomariov's f5 on move 12 hit the board.
I completely missed the line with f5, Nakamura said. It was a very good move by Ruslan and I pretty much underestimated it.
Donaldson asked Nakamura if he thought about castling queenside. The 2009 U.S. champion said if it were a must-win game he would have considered it. But after winning yesterday to pull even in the match, he said the last thing he wanted was a loss.
I didn't win, but its not the end of the world, Nakamura said.
After the game, Ponomariov was asked about his style of play.
Maybe, somehow, I like to outplay my opponent slowly, move positionally, get more endgames. Hikaru, at the same moment, he has a lot of energy and is fighting in every position and keeps the tension.
The round 4 Robson-Finegold match was a well played gamed by both sides, Shahade said.
This game could be of theoretical importance, said Donaldson, the author of two books on the Dragon. He pointed to Finegolds Qb6 instead of Qc5 on move 19. White never had anything. Qb6 equalized very comfortably.
Robson never castled and had pawns on a4 and h4 at one point. Finegolds queen on a5 discouraged queenside castling. But Robson said Finegold told him he should sacrifice a pawn and castle queenside.
Finegold's e5 on move 28 probably just forces a draw the young grandmaster said. He had to capture en passant.
Somehow I underestimated that move, he said.
To follow the games live, visit saintlouischessclub.org/nakamura-v-ponomariov-robson-v-finegold/live. Live commentary by IM John Donaldson and WGM Jennifer Shahade can be found at livestream.com/uschess. Rounds and commentary are open to club members, and memberships start at just $5/month for students or $12/month for adults.