Key Points
  • Sudoku (数独) means "single digit" in Japanese
  • Full phrase: sūji wa dokushin ni kagiru — "the digits must remain single"
  • Named by Japanese publisher Nikoli in 1984
  • The original puzzle was called "Number Place" when invented in the USA in 1979
  • The name perfectly describes the rule: no digit can appear more than once per unit

Breaking Down the Word

The word 数独 combines two kanji characters: 数 (sū, meaning "number" or "digit") and 独 (doku, meaning "single" or "alone"). Together they mean "single digit" — a compact description of the rule that no digit may repeat in any row, column, or box.

The full phrase the name is drawn from is 数字は独身に限る (Sūji wa dokushin ni kagiru), which translates as "the digits must remain single" or "only single digits allowed." Nikoli shortened this to 数独 when they trademarked the name in Japan.

The Western Origin

Before Nikoli gave the puzzle its famous name, it was published in the United States by Dell Magazines in 1979 under the plain title Number Place. The puzzle was created by Howard Garns, a 74-year-old retired architect from Indianapolis who contributed logic puzzles to Dell under a pseudonym.

Number Place ran without much fanfare in the US for five years before Nikoli discovered it, brought it to Japan, and built it into a cultural phenomenon. By the time it returned to the Western world in 2004, it had the Japanese name that has stuck ever since.

How a Name Became a Brand

Nikoli trademarked the name 数独 in Japan, which is why Japanese puzzle books by other publishers often use alternative names for the same puzzle. Outside Japan, the name Sudoku was never trademarked, which is why it appears freely on websites, apps, and newspaper columns worldwide.

The name also helped the puzzle travel: "Sudoku" is pronounceable in almost every language, unlike "Number Place," which assumes familiarity with English. The short, memorable sound contributed to how quickly the puzzle spread globally after 2004.

What the Name Teaches You About the Game

Knowing that Sudoku means "single digit" gives you the rule in the name itself. Every technique in the solving techniques library is just a systematic way to find which digit must remain single in which cell.

If you are new to the puzzle, start with an Easy puzzle. If you want to understand the history in more depth, read our full article on the history and global origin of Sudoku.