TCEC S19 DivP Started; CCC15 in Brackets

Two weeks ago, the title of the post, TCEC S19 Underway; CCC in 'Pre-CCC15' (August 2020), gave the overall status of the two leading engine vs engine tournaments. The following summary gives some of the details.

TCEC: Before the start of Season 19 (S19), the TCEC announced its format; the organizers are following the same format they used in S18. A new engine 'SlowChess' won both QL and L3 by significant margins. The site is now in testing for League 2 (L2). • CCC: The 'AlphaZero Simulation Match' finished with Lc0 beating Stockfish 8, the version used in the 2017 AlphaZero - Stockfish match. After that ended, the CCC started running a series of 'Pre-CCC15' events. The name of the next event will be 'CCC15: Bullet II' and it should start this week.

In the meantime, both tournaments have completed subsequent stages.

TCEC: Losing only L2 one mini-match to 1st placed Igel, SlowChess finished 2nd to qualify for L1. There it finished 3rd, a half point short of qualification into the Premier Division (DivP). Fire and ScorpioNN qualified into DivP, which is just getting started and which will run for almost three weeks. The top two engines will qualify into the final match (aka Superfinal or Sufi).

CCC: In my previous post ('CCC in Pre-CCC15'), I noted,

A preliminary document showing the planning for CCC15 is available, but is too cryptic to understand.

It turns out that CCC15 is a straightforward bracket structure starting with a preliminary round-robin equivalent to 12-game mini-matches. That event determined the starting positions for the brackets. The structure of the first three rounds of CCC15 is shown in the following chart.

Stockfish won the preliminary event ('Round 1') by a significant margin. Since there were 17 engines, the two last-placed engines played a qualification match for the 16th place:-

CCC15.01 has been stopped on account of awfulness, and Defenchess declared the winner [over Winter].

Thus spake the arbiter: 'stopped on account of awfulness'. The 'Round 2' matches are underway and the world waits eagerly for the result of Stockfish vs. Defenchess. Will it be a whitewash?

[For further information from the various stakeholders in the engine-to-engine events, see the tab 'TCEC/CCC Links' at the top of this page. • NB: Leela = LC0 = LCzero]