What is vd12?

VD12, also known as "Very Deep 12," refers to a specific variable depth integration technique used in some advanced chess engines. The "12" indicates the maximum ply (half-move) depth the engine searches in certain lines.

In chess engine design, variable depth integration allows the engine to analyze critical lines of play more deeply than less promising ones. VD12 would mean an engine can search up to 12 ply in crucial positions, but it may search to a shallower depth in quieter or less strategically important positions. This adaptive search allows engines to efficiently allocate computational resources. Key improvements that VD12 provides are better tactical calculations and an increased ability to assess positional advantages accurately. VD12 assists with pruning bad moves earlier in the search, allowing the engine to focus on the best possibilities.

It's important to note that VD12 is just one aspect of a chess engine's architecture, and its effectiveness depends on its integration with other search enhancements and evaluation functions.