There are more possible games of chess than atoms in the observable universe.

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Where the number comes from

In 1950, mathematician Claude Shannon estimated that a typical chess game offers about 1,000 possibilities for each pair of moves (one by White, one by Black), over about 40 such pairs. That gives roughly 10¹²⁰ possible games, a 1 followed by 120 zeros, and he called it a conservative estimate.

Compared with the universe

The observable universe is estimated to contain around 10⁸⁰ atoms. Even the number of legal positions on a chessboard is enormous: about 4.8 × 10⁴⁴.

Why it matters

Numbers this big are why chess hasn't been "solved". Computers play brilliantly, but nobody has worked out perfect play from the starting position. Only endgames with up to seven pieces have been solved completely.

Test yourself

Sources

• Wikipedia: Shannon number
• Wikipedia: Solving chess

Fact-checked 14 October 2026 · Report a mistake