Draw rate, wins
Final draw rate was 50.0%.
The three most common game termination causes were:
46.4% - TCEC win rule
19.6% - TCEC draw rule
18.8% - TB position
There was one crash in the division.
Moves per game
The game lengths were similar to those in division 3.
Time per game (hours)
There were 2-move book openings in this stage chosen by Cato. The first letter of the ECO codes was
distributed as follows:
For each round all four games had the same book sequence, and again
in the reverse round. There were 14 book sequences, each repeated 8
times. For some sequences all the openings had similar codes (e.g.
Sicillian or French). In others the engines had more freedom to choose
(in rounds 17 and 24 there were 4 Grunfelds, 3 King Indians and one Maroczy Bind Sicilian).
If we use the opening 'family name' (using format FAMILY_NAME: VARIANT....) the top 3 are:
Sicillian - 25 times
English - 9 times
QGA - 9 times
Queen's Pawn - 9 times
engines had a lot of freedom to choose the opening variant. 39.3%
of the game pairs repeated the same ECO code twice, and 16.1%
repeated the same opening variant. In 12.5% of the game pairs the ECO
first letter was not repeated twice.
Reverse pairs, wins
There were 6 game pairs with a 1-1 biased result. It is likely that the engines playing have more influence on the outcome than the 2-move opening, especially when other games with the same opening have different results.
Reverse pairs, same moves
Pairs of reverse games diverged very quickly, 46.4% of the pairs
diverged immediately after book, 87.5% repeated at most 2 plys. The maximal repeat length was 9 plys (rounds 19 and 26, Arasan - Jonny).