TCEC Cup 4

This is a report of the 'TCEC Cup 4' computational experiment, the 4th TCEC knockout event and the second major part of TCEC’s 16th season. It started on 16th October 2019 and featured the best 32 engines of the ‘TCEC 16’ league event and the games were held at Blitz tempo, The different format called for different optimal settings in the engines, thereby enabling a comparison with performance at slower tempi. STOCKFISH retrieved the title from LEELA CHESS ZERO, defeating it when their perspectives diverted on move forty of game eight. All decisive games in the supplementary data have been played out by FRITZ17 at search depth 24 to enable and benchmark endgame practice.