Kakuro

Kakuro is a logic number-placement puzzle originally invented as 'Cross Sums' by Jacob E. Funk for Dell Magazines in 1966 and popularised globally under its Japanese name from Nikoli in the 1980s. Solvers fill a crossword-like grid with digits 1-9 so that each vertical or horizontal run sums to the clue printed in the black cell at its start — and no digit repeats within any single run.