Tokyo: Maki Kaji, the Japanese man known as the “Godfather of Sudoku,” has died at the age of 69. On Monday, ‘Nikoli,’ the first puzzle magazine in Japan published a statement on its website saying Kaji had died at his home in Tokyo from bile duct cancer on Aug. 10, 2021. He leaves behind his wife and two daughters.

Kaji gave the number puzzle its name after publishing it in his magazine Nikoli in the 1980s. Since then the popular game – involving placing the numbers 1 to 9 in each row, column and square of a 9 by 9 grid – has spread around the globe. Tournaments take place across the world and it is estimated that millions play versions of the game each day.

“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,” the company said in a statement.

Kaji did not trademark the game, and did not gain financially from its huge success. But he said the joy of the puzzle and of others enjoying the game was more important than any                       monetary reward.