Rybka - 5

: When used within the Aquarium interface, IDeA allows you to build a comprehensive "tree" of variations. It doesn't just show you the best move; it explores why other plausible moves fail and visualizes the long-term consequences, effectively producing a complete map of a complex position.

: This feature allows the engine to "remember" previously analyzed positions across different sessions. This is critical for producing a "good" feature in a long-term project, such as building an opening repertoire, as the engine becomes faster and more accurate the more it re-visits a line. Rybka 5

: For a standard quick check, a depth of 5 (2.5 full moves) is the default, but for high-quality features, you should aim for 18–20+ plies to find deep tactical or positional breakthroughs. : When used within the Aquarium interface, IDeA