TCEC S15, CCC6 S3 : Both Underway

In last week's post, TCEC S14/S15 Interlude; CCC6 S2 Wrapping Up, we left the two ongoing engine-to-engine competitions both preparing for their respective next stages. What has happened since then?

TCEC: In the 'S14/S15 Interlude' segment of the post I mentioned 'three short competitions', aka bonus events, that were conducted between the end of S14 and the start of S15:-

The first event was a 48-game three-way match that lasted a day or so. • The second event was a 240-game four-way round robin featuring the four top engines: Houdini, Komodo, Leela (LCZero), Stockfish. I couldn't find a final crosstable for the event, although the final PGN is available in the TCEC archive. • The third event was a 100-game match between Stockfish and Leela that lasted about three days.

It turned out that I was referring to an old archive, one that uses the site's old GUI. A new archive, based on the new GUI, is at tcecbeta.club/archive, under 'Seasons', and has all of the info that I was looking for last week. I added the new archive link to the 'TCEC/CCC Links' tab at the top of this page. For the S15 kickoff report from TCEC, see

• 2019-03-05: TCEC Season 15 – To A/B or NNot to A/B, That is the Question (chessdom.com)

The report includes a list of competitors for each stage of the new season. The first event, 'S15 - Division 4a', has already finished and 'Division 4b' is underway.

CCC: Chess.com issued a report on the current status of its CCC:-

• 2019-03-09: Stockfish Faces Lc0 In Computer Chess Championship Finals (chess.com)

The 200-game match started two days ago and is moving quickly, with about 1/4 of the games already finished. The two engines, Stockfish and Leela (Lc0), are running neck-and-neck.