This is the core pruning algorithm inside minimax search.
✔ Analogy
Instead of checking every path in a maze, you stop exploring a path when you already know it’s worse than a path you saw earlier.
✔ Why it matters
It eliminates useless branches of the game tree.
✔ What it does
- Keeps track of best score for maximizing player (alpha)
- Keeps track of best score for minimizing player (beta)
- If a branch can’t possibly improve the outcome → cut it off immediately.
✔ Example
If Stockfish finds a checkmate in 5 on one branch, it doesn’t waste time analyzing a losing variation for you.
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All notes