Maki Kaji, the beloved creator of the zeitgeist numbers puzzle Sudoku, has died after a battle with bile duct cancer. He was 69.
The “Godfather of Sudoku” passed away on Aug. 10 at his home in the Tokyo metro city of Mitaka, his company announced on Tuesday. He remained chief executive at Nikoli Co. until July.
Kaji was born in 1951 in Sapporo and later competed at the National Sports Festival with his high school tennis club. After two and half years studying at Keio University, he dropped out due to numerous class cancellations spurred by the 1970 protests against the Japan-US. Security Treaty, according to his obituary in the Japanese news outlet Mainichi.
Kaji established Japan’s first puzzle magazine, Puzzle Tsushin Nikoli, with pals in 1980. His most legendary creation, Sudoku, followed in 1983.
However, it wasn’t until 2004 that Sudoku would became a global sensation, after a fan from New Zealand pitched it to the British newspaper The Times, the Associated Press reported. Two years after its publication in the UK, Japan rediscovered its own puzzle as a “gyakuyunyu” — or “reimport.”
“I don’t want to just be the godfather of Sudoku,” Kaji once said in an interview. “I’d like to spread the fun of puzzles until I’m known as the person who established the puzzle genre in Japan.”
Kaji also said he created Sudoku to be easy for kids and anyone else who didn’t want to think too hard. The puzzle’s name is made up of the Japanese characters for “number” and “single,” and players place the numbers 1 through 9 in rows, columns and blocks without repeating them.
He traveled to more than 30 countries spreading the “joy of puzzles,” with Sudoku championships eventually drawing some 200 million people in 100 countries over the years, according to Tokyo-based Nikoli.
Sudoku was actually never trademarked except within Japan, driving its overseas craze, the company has said in a statement: “Kaji-san came up with the name Sudoku and was loved by puzzle fans from all over the world. We are grateful from the bottom of our hearts for the patronage you have shown throughout his life.”
Sudoku was originally dubbed “Suji-wa-Dokushin-ni-Kagiru,” which translates to “Numbers should be single, a bachelor.” Now believed to be the world’s most popular pencil puzzle, Sudoku has recently debuted in digital versions to keep up with the times.
Yoshinao Anpuku, who succeeded Kaji as Nikoli’s chief executive, said his old boss made friends easily and had a “unique and playful approach toward life.”
“Our mission is to pursue Maki’s vision and possibilities,” Anpuku said of the man Japanese news outlets credited for starting the puzzle sections at bookstores, as well as introducing the word “Sudoku” into the Oxford English dictionary.
His work has also had potentially long-lasting impact on the human brain: A 2019 study of 19,000 adults over 50 years old finds that older people who do daily number and word puzzles have sharper brains, according to the findings published in the International Journal of Geriatric Psychiatry.
The participants were asked how frequently they did puzzles like Sudoku, and then completed a series of tests that examined their attention, reasoning and memory.
“The improvements are particularly clear in the speed and accuracy of their performance,” said lead researcher Dr. Anne Corbett, of the University of Exeter Medical School. “In some areas the improvement was quite dramatic.”
Kaji is survived by his wife Naomi and two daughters. Funeral services have been held among close family and a separate memorial service is being arranged by Nikoli.