TCEC S14/S15 Interlude; CCC6 S2 Wrapping Up

Getting back to the top-two chess engine competitions of our time, the title of last week's post, Stockfish Wins TCEC S14; CCC6 S2 Underway, summed up the situation well enough. What has happened in the intervening week?

TCEC: Chessdom issued reports on the results of S14:-

• 2019-03-01: Stockfish continues to dominate computer chess, wins TCEC S14
• 2019-03-02: The TCEC14 Computer Chess Superfinal: a perspective (by GM Matthew Sadler)

After the finish of S14, while S15 preparation was underway, the site conducted three short competitions. The first event was a 48-game three-way match that lasted a day or so. It finished with the result Stockfish 17.5/32, Leelenstein 16, Antifish 14.5. According to the site's Nightbot chat,

Leelenstein aka Dr. Leelenstein, aka The Doctor, is a 20x256 SE net built using games from CCRL, Sergio's 40 block variant, and T30. Novelties: TP + GGT + SGDR • AntiFish is a Neural Network [...] designed to exploit weaknesses within Stockfish. The hope is that one day AntiFish can be used to improve Stockfish itself.

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 (see the 'TCEC/CCC Links' tab at the top of the page for references). This event was documented better in the archive than the preceding 48-game three-way match, which is also missing the final PGN.

The third event was a 100-game match between Stockfish and Leela that lasted about three days. I couldn't find any trace of this event in the archive, but one post-match reference in the Leela forum, Leela - Stockfish "no opening book" match results, said, 'Final result: Leela 56, Stockfish 44. Leela: +16-4=80'. What 'no opening book' means is anybody's guess. It appears to have favored Leela substantially.

The TCEC has so far issued one announcement about the new season, due to start this week:-

• 2019-03-02: Allie+Stein, the new neural network entering TCEC S15 (chessdom.com) • 'Season 15 is about to start and one more neural network is going to enter TCEC. This is a combined project by Adam Treat and his Allie and Mark Jordan and his Leelenstein. The new engine is called Allie+Stein, a unique engine by the TCEC rules that will start its quest for top positions and climb of the ladder from Division 4'

Both AI/NN engines, Allie and Leelenstein, competed in CCC6 stage 1, with markedly different results.

CCC: As for CCC6 stage 2, the event is nearing completion with Stockfish in a comfortable lead. It will face the second placed engine in a 200-game match.