2026-07-23 · history
Slitherlink (1989) — Loop-Closing Logic Born From a Two-Player Paper Game
In June 1989, barely half a year into the Heisei era, Puzzle Communication Nikoli #26 introduced a new puzzle format. Adapted from a two-player paper game called Slither into a single-player pencil puzzle, Slitherlink offers a paradoxical solving pleasure — proving where lines cannot go rather than where they can — and carries a nearly 38-year lineage running through NP-completeness proofs to Steam storefronts in the 2020s. We trace, with sources, the loop-logic Nikoli founder Maki Kaji once called "the son of Sudoku."