Rodent IV is unusual, and it is the reason the historical master bots on this site play the way they do. It accepts personality configuration files that change how the engine weighs different aspects of a position — king safety, pawn structure, piece activity, the value of the initiative, willingness to accept material imbalance.
That is a fundamentally different way of making an engine play like a person than the usual approach. Most "1400 bots" are a world-class engine instructed to make mistakes at a certain rate, which produces excellent moves with random errors sprinkled in — nothing like how any human plays.
A personality file instead changes what the engine wants. Set it to value the initiative extremely highly and it starts sacrificing material for attacks. Set it to prize king safety above all and it plays prophylactically and refuses to commit. The moves are still competently calculated; the goals are different. That is why Tal and Petrosian on this site produce genuinely different games rather than the same game with different error rates.
What makes it distinctive
- ▸Personality files change evaluation weights, not error rates
- ▸Powers all six historical master personas on Chessy
- ▸Can be configured across a very wide strength range