The History of Slitherlink
Unlike Kakuro or Sudoku - both puzzles that started life elsewhere and only later passed through Japan - Slitherlink is a home-grown Nikoli invention from the start, with no earlier Western original to trace back to.
A Nikoli Original
Slitherlink was first published in 1989 by Nikoli, the Japanese puzzle company already responsible for popularizing (and naming) Sudoku and Kakuro internationally, in one of its own puzzle magazines. Unlike those two, Slitherlink wasn't an import Nikoli picked up and refined - it's one of the company's own original inventions, credited to its regular contributors the way Nikoli credits many of its puzzle types.
Its Japanese name is often rendered in English simply as "Loop the Loop," a fair description of the goal: every clue in the grid exists only to pin down the path of one single, unbroken, non-crossing loop.
A Different Kind of Grid Puzzle
Where Sudoku and Kakuro ask a solver to fill cells with digits, Slitherlink asks something structurally different: draw lines between fixed points until they form one closed shape. That makes it a closer cousin to Nonogram's picture-logic and Kakuro's run deduction in spirit - reason from the clues alone, never guess - while looking nothing like either of them on the page. Solving one never requires arithmetic or language of any kind, only the same handful of local deductions (a 0 forces its edges blank, a corner with two lines already drawn forces every other line at that dot blank, and so on) applied over and over until the loop closes.
That language-independence is exactly what let it, like Nikoli's other logic puzzles, travel well: a Slitherlink grid published in a Japanese magazine needs no translation to be solved anywhere else in the world.
Joining the Wider Puzzle Family
Slitherlink spread internationally through the same wave of interest in Nikoli's catalog that carried Sudoku to newspapers worldwide in the mid-2000s, appearing under various names - Fences and Loop the Loop both stuck in English - in puzzle books, magazines, and eventually mobile apps and websites everywhere.
It's now a well-established member of the same family this collection already includes several of: pure-deduction logic puzzles that need no shared language or arithmetic to enjoy, generated fresh here with a computer-verified guarantee that every board has exactly one valid solution, the same way this collection's Sudoku, Kakuro, and Nonogram puzzles are.