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Body & Mind · 2026-06-14

How Chess Masters Remember: The Secret Is “Chunking”

A master can rebuild a whole board from a glance — but only if the position makes sense.

Show a grandmaster a real position for five seconds and they can rebuild it almost perfectly. Show a beginner the same board and they manage a handful of pieces. For decades that gap has been one of psychology's favorite windows into expertise.

The classic experiment

In the 1940s the Dutch psychologist and master Adriaan de Groot noticed that strong players seemed to see a position as a few large, meaningful wholes rather than 32 separate pieces. In 1973, William Chase and Herbert Simon turned this into a theory: experts store the board as chunks — familiar clusters of pieces — and a master may hold tens of thousands of them, often estimated at around 50,000.

The decisive detail: when the pieces are placed at random, masters lose their edge and recall little better than novices. Their memory isn't photographic — it is pattern-based. They remember meaning, not pixels.

Why it matters beyond chess

Chunking is now a cornerstone of how we understand skill of every kind — music, mathematics, medicine, sport. Expertise is, in large part, a vast library of recognized patterns built through years of exposure. The master isn't calculating more raw moves than you; they are seeing the board in a richer alphabet.

It also explains why study beats mindless play: every game you analyze adds chunks to your library, which is why pattern-rich training — tactics, classic games, endgames — pays off.

In short: Masters recall real positions almost perfectly but do no better than novices on random ones: their memory is pattern-based 'chunking', with an estimated 50,000 patterns built over years.

Frequently asked questions

How do chess grandmasters memorize positions so well?

Through 'chunking': they store the board as a few familiar clusters of pieces rather than many separate ones. Masters are estimated to hold around 50,000 such patterns, built over years of study.

Do chess masters have photographic memory?

No. When pieces are arranged at random, masters remember little better than beginners. Their recall is pattern-based — they remember meaningful structures, not images.

Who discovered chess 'chunking'?

Adriaan de Groot observed it in the 1940s, and William Chase and Herbert Simon formalized the chunking theory in 1973. It is now a foundational idea in the study of expertise.

See also

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A curiosity from History's Gambit, where chess meets history. You may cite or describe it with attribution to historysgambit.com.