You can download Slow Chess 2.6 from
https://www.3dkingdoms.com/chess/slow.htm
It scores +60 elo to 2.5 in bullet self-play games. (2-moves book, 8-moves book, herz book)
The main feature is a new network structure detailed in this forum thread, which combined with consistently running more training games overnight when my computer is free has resulted in a good increase in strength.
While I was pretty excited to see clear improvement, I still have a long Todo list. I'm hoping to eventually release at least a couple more version before calling it good. Some of the weaknesses I noticed
- It is becoming very slow with the larger evaluation. I just measure Elo so this is fine by me, but I think on some other computers especially older ones the current structure probably isn't the best. (I may never get around to trying to sort this out, but maybe can make some general optimization and try testing on an older computer.)
- FRC is still very bad compared to standard. I think this structure will be better for FRC, but I will need to start training FRC at some point and make sure it doesn't hurt standard.
- The own book just doesn't cut it at this level. I tried running more book gen, but my book gen doesn't remove losing lines, and there are a lot of the lines are left from around the 2800 elo range where a greater variety is playable.
- The net still doesn't seem big enough to detect things like totally trapped pieces. I was surprised how often I saw this in losing games against the strongest opponents like SF11.
- I've stubbornly never even looked at NNUE except getting a general sense of it during the initial hype, so again the only net compatible with 2.6 is the one that ships with it. I'm not sure if I will add support, given the progress of NNUE engines especially stockfish, I can only assume using the nnue-ecosystem would quickly improve over my current efforts. Then I'd be left with the dilemma of whether or not to do the experiments that seem interesting to me (it's nice not to be too strong... there's a much higher chance of clear success trying something new. To be clear I think SF has at this point changed or replaced most of the original NNUE from what I read? But I'm unlikely to improve current best on my own.)
