2026-07-25 · history
Kakuro (1966) — From Cross Sums to Addition Cross, Sixty Years of an Unmoved Grid
Kakuro, known in English as Cross Sums, began in 1966 as a Dell Magazines feature. Nikoli brought it to Japan in the 1980s and renamed it 'kasan kurosu' (addition cross); in 2005 it was re-exported to the world via The Guardian. This essay traces why this grid of arithmetic — neither crossword nor Sudoku, but a hybrid of both — kept its rule unchanged across sixty years of shifting media, from paper magazines to a Nintendo DS cartridge to today's Steam store pages.