Season 8 stage 3 rounds 16-20

After 20 rounds (4 RR) the crossable is:

What a turn-around. Gull drops from first to third in the fourth RR. Komodo is now comfortably in the lead, and Stockfish is second (remember its two losses on time in the first RR, losing 1.5 points including 0.5 to Gull). This is what was expected so there is less tension for the fans (especially SF fans like me). However, Gull has proven it is very strong and hard to beat, and with only 10 games per Engine left anything can still happen.

Komodo was on fire this RR with a result of 4.5/5. Only Stockfish could get a draw against it.

Protector-Hannibal managed to find a draw faster than the reverse game, this time in 19 moves. Protector also had two wins in the fourth RR, after only one in the first 3 RR (not counting the game against Stockfish which was lost). The first win was against Houdini after a long shuffling match. The second win was against Gull with the assistance of the king's gambit opening.

Hannibal held for 30 moves against Komodo, but blundered in the end to allow Komodo to reach a won rook ending.

Stockfish managed to get a draw out of its hard opening against Gull.

Notable game
Komodo-Gull, round 16
Game on TCEC archive

The opening favoured white but nothing Gull couldn't handle, right? On move 22 the position was:

The queen side was locked with pawns but the g file was open after Gull advanced its king side pawns. That left both kings a bit open to attack, not clear where black's king can go and how to develop black's queen and rook. Komodo then placed two rooks on the g file while Gull tried to untangle itself by attacking the center:

This was a serious mistake because Komodo used a bishop and knight on both sides of the board to trap Gull's king in the center and freeze the queen side entirely:

Komodo then opened up the king side, temporarily giving up a rook for a bishop but clearly in the lead. Gull gave back the exchange to get rid of the knight on b6 and was only a pawn down when the dust settled:

The evals show the reality of the position. After exchanging the rook and queen the combination of a passed f-pawn and all the black pawns on white squares ensures the win for white.