woensdag 10 juni 2020

Opening selection TCEC 18 superfinal

Here are Jeroen Noomen's comments on the opening selection for the TCEC 18 superfinal:

"Here are the most important details regarding my selection of the openings for the TCEC 18 superfinal:
  • The book was completed in December 2019 and is the result of the (for me) disappointing TCEC 16 superfinal; in this superfinal it became clear to me that my usual opening selection method was not working anymore
  • All important openings will be played; in this superfinal, however, there will be a lot more risky opening lines compared to S16 and before
  • The chosen lines typically have a length between 1 move and 12 moves; there is one line which is only 1 move (i.e. the first white and black move), there is one line with 16 moves of book
  • I have chosen a couple of S16 user bonus lines, a line from a Karpov-Korchnoi match and in this superfinal we will also see the return of the King's gambit, which was absent in S17
  • Average move length is 7.04
  • There are sharp lines in the set, as well as positional linesmore complex lines, lines with opposite castling ("SALC", i.e. short and long castling), dubious lines, lines with an imbalance in material and gambits
  • Some lines are borrowed from previous superfinals, they can be the same, somewhat shorter, or longer, if necessary
  • The complexity of a position is one of my main selection criteria, i.e. most pieces are still on the board and there should be a lot of play left, with a reasonable chance for a decisive result. Compared to previous superfinals the book exit evaluations are mostly significantly higher. This has been checked with Stockfish (development version, contempt = 0) on a 16 core Ryzen system and Leela Chess Zero, with a December net that was suitable for my hardware
  • In each line one side typically has an advantage, so each engine gets the chance to push for a win, while in the return game it has to defend the weaker side
  • I have avoided positions that could lead to many exchanges and/or have a high draw rate, as well as positions with symmetrical pawn structures and positions that could lead to easy wins for the side with an advantage. I also have avoided 'easy', very solid, classical positions, in which there is almost no chance for the engines to go wrong and where the expected draw rate will be very high (>90%)

ECO code distribution
ECO A: 12 lines
ECO B: 13 lines
ECO C: 11 lines
ECO D: 4 lines
ECO E: 10 lines

Preferable opening results
My personal ranking of desired opening results (i.e. 2 games with each line) is as follows:
  • 2-0  This is very rare, nevertheless we had such a result in the S14, S15 and S17 superfinals
  • 1.5-0.5  One engine wins the opening minimatch
  • 1-1 with both engines winning hard fought games, that are not the result of the chosen opening
  • 1-1 with both engines drawing and the draws being very interesting and fiercely contested
As you can see, I don't object against 1-0 1-0 (or 0-1 0-1) results anymore, I now find them slightly more desirable than two hard fought draws. This is a new insight for me, as before S17 I regarded a 1-0 1-0 result as rather undesirable.

The two results I want to avoid, is 1-1 with two very onesided wins or two very boring draws, where the result is already clear shortly after the engines left book.

A personal note
My sources to select openings for the TCEC superfinals are: GM games, correspondence games, databases, chess books, theoretical websites and my personal opening experience. I prefer lines that have a rather low draw rate in correspondence chess, i.e. preferably 50% or lower.

Personally I am a big fan of original, enterprising, lively, complex and non-standard play. In my opinion lines in this category can lead to far more interesting games than in the usual solid, classical stuff. Hence my opening selection reflects that preference.

Nevertheless, my picks will also always include well known opening lines, as long as they don't have a high chance of a draw. Please note that simple, classical, open and standard opening positions just have a very high chance of a draw, especially under TCEC superfinal conditions and with the TCEC hardware. We want to avoid >90% draws, therefore I exclude such lines from my selections. I understand that might not be to everybody's liking, but I'd say: if we have a lot of exciting games, this is the way to do it!

How many wins do I expect? Well, in the S17 superfinal we had 29 wins, which was quite a lot higher than I expected. As my S18 picks are a lot riskier, I expect a minimum of 25 wins and I think that more than 30 wins are entirely possible.

So: have fun! I hope you enjoy the games and we will see lots of exciting chess and dramatic turn of events, like we had in all previous superfinals!"

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