Koivisto is an independent open-source engine that developed its own NNUE-style network training pipeline rather than borrowing one. For a period it was among the strongest engines not derived from Stockfish, and it remains a reference point in the engine development community.
Like Reckless, its value here is partly that it is genuinely different. Two engines built by different people, trained on different data, will disagree about positions — and those disagreements are usually the positions worth looking at.
It is also a good demonstration of how far a small independent project can get. Computer chess has a reputation as a solved problem dominated by one program, and the existence of several strong unrelated engines is a useful correction to that.
What makes it distinctive
- ▸Independent engine with its own network training pipeline
- ▸Strong enough to make Stockfish work for a win
- ▸A good second opinion when two engines disagree about a position