There are more possible games than atoms in the visible universe
The mathematician Claude Shannon worked out one of the great mind-bending numbers of chess. He estimated that the number of possible chess games is around 10 to the power of 120, a 1 followed by 120 zeros. People often say such a number is larger than the number of atoms in the observable universe, which is a much repeated and reasonable comparison. More recent estimates are even bigger: the game-tree complexity of chess is often put at something like 10 to the 123rd power. Whatever the exact figure, the point stands. No two games, in any sense that matters, could exhaust them all.
"Checkmate" comes from a Persian phrase
The word checkmate traces back to the Persian phrase shah mat. Many popular explanations translate it as "the king is dead," but the more careful reading, favored by etymological dictionaries, is "the king is helpless." Either way, the lineage is a reminder of where chess came from. Even the word "chess" and "check" carry that Persian root for "king," shah.
Chess has been played in space
The game reached orbit decades before most people think. During the Soyuz-9 mission in 1970, cosmonauts played a game against the ground, calling moves over the radio; it is said to have ended in a draw. Half a century later, in June 2020, the grandmaster Sergey Karjakin played two cosmonauts, Anatoly Ivanishin and Ivan Vagner, on board the International Space Station, in a match held to celebrate that first cosmic game. It, too, ended level. Space does not seem to scare chess.
The board is 64 squares, and everyone brings 16 pieces
The board is a simple 8 by 8 grid, which makes 64 squares, half light and half dark. Each side starts with 16 pieces: eight pawns, two rooks, two knights, two bishops, one queen, and one king. So on a full board, 32 pieces in total are in play.
One rule was born of another
The pawns gained the option of moving two squares on their first move, and that rule created an awkward gap. A pawn could now slip past an enemy pawn and avoid capture entirely. So the en passant rule was added, letting that enemy pawn capture it as if it had moved only one square, but only on the very next move. Chess's strangest rule exists just to patch a hole opened by an earlier change.
One man held the longest unbeaten run
Mikhail Tal, "the Magician from Riga," once went 95 games across a year without a loss, a record that stood for decades. It was finally beaten only in the late 2010s. For a player famous for risky, inventive attacks, that kind of consistency is remarkable.
Chess is full of facts like these: numbers too large to picture and details carried across a thousand years of history. It is part of what makes such a small game so endlessly interesting.