Yajilin

Yajilin is a logic puzzle played on a rectangular grid in which the solver draws a single continuous loop that never crosses or branches. Some cells in the grid start out marked with a number and a directional arrow, indicating exactly how many black, wall-like cells must appear somewhere along the row or column the arrow points down; the rest of the grid's cells are then fixed by deduction until every cell is determined as part of the loop, blank, or a black wall. The Japanese puzzle publisher Nikoli introduced Yajilin in issue 86 of its magazine Puzzle Communication Nikoli in June 1999. The puzzle has also circulated under the English name Arrow Ring, used for instance in the 2005 United States qualifying test for the World Puzzle Championship. Its Japanese name blends yajirushi, meaning a directing arrow, with the English word link.