Guides
The evergreen reference: what an engine is actually measuring, and how to use its answer without being misled by it.
Piece Values Are Not 1, 3, 3, 5, 9
The values every beginner learns are a rounding of numbers that were never whole, and modern engines do not use fixed values at all. What replaced them.
4 min read
The Horizon Effect
An engine can hide a bad outcome by pushing it past the end of its search, usually by giving material away. How to spot an evaluation that is doing this.
3 min read
The Eval Bar, and What It Hides
The bar is a picture of one number, compressed so that small advantages look large and large ones look similar. What it is good for and where it misleads.
4 min read
What NNUE Changed About Engine Evaluation
Until 2020 Stockfish scored positions with rules people wrote. Now a small neural network does it. What changed in the numbers you read, and what did not.
4 min read
How to Analyse Your Own Game Without Wasting an Hour
Most engine reviews are read once and forgotten. A repeatable method that produces two or three things you will actually remember, in about fifteen minutes per game.
3 min read
Blunder, Mistake, Inaccuracy: Where the Lines Are
The three labels come from fixed centipawn thresholds that differ between sites. What each one means, why the boundaries are arbitrary, and which ones to study.
3 min read
Average Centipawn Loss, and What It Does Not Tell You
ACPL averages how much value each of your moves gave away. It is a useful number with three specific blind spots, and one of them makes losing games look good.
4 min read
When the Best Move Is Not Your Move
The engine assumes your opponent finds every reply. Below master level that assumption is wrong often enough to change which move actually scores best.
3 min read
Depth, and What It Buys You
Depth 20 is not twice as good as depth 10. What a ply is, why the returns fall away sharply, and how to tell when a position has actually been resolved.
3 min read
What the Evaluation Number Actually Means
An engine's score is measured in pawns, but it is not counting pawns. What the number is, what counts as an advantage, and why anything under 0.3 is noise.
3 min read