Yajilin (ヤジリン) is a type of logic puzzle published by Nikoli. It has been published in English under the name Arrow Ring, such as in the 2005 U.S. qualifier for the World Puzzle Championship. A logic puzzle is a puzzle deriving from the mathematics field of deduction. ... Jump to: navigation, search Nikoli is also a village on the island of Lefkada, see Nikoli, Greece Nikoli (ニコリ) is a Japanese publisher that specializes in logic puzzles. ...

Rules

Yajilin is played on a rectangular grid of squares. At the beginning, cells are either indicative (containing a number and an arrow pointing "up", "down", "left," or "right") or empty. Through the course of solving, some non-indicative cells may be determined to be "black" (to be shaded in by the solver).

The goal is to draw a single continuous non-intersecting loop that passes through each cell that is neither black nor indicative. The loop must "enter" each cell from the centre of one of its four sides and "exit" from a different side; all turns are 90 degrees. A degree (in full, a degree of arc), usually symbolized °, is a measurement of plane angle, representing 1／360 of a full rotation. ...

For each indicative cell, its number indicates the count of the black cells that lie in that row or column in the direction of its arrow. Indicative cells can never be black, and do not count as a black cell for the purpose of satisfying other indicative cells, although the loop cannot pass through them.

On a solved board,

• Every non-indicative cell is either black or contains a segment of the loop.
• Every indicative cell is accurate. For example, if an indicative cell has an arrow that points to the left and the number '3', there must be exactly 3 black cells to the left of that indicative cell in the same row.
• Black cells do not touch each other orthogonally (they do not share a side).

There may be black cells that are not accounted for by the indicative cells. Jump to: navigation, search In mathematics, orthogonal is synonymous with perpendicular when used as a simple adjective that is not part of any longer phrase with a standard definition. ...

History

Yajilin is an original puzzle of Nikoli; it first appeared in Puzzle Communication Nikoli #86 (June 1999). The name is Japanese, in which it is a contraction of yajirushi (directing arrow) and linku (the English word 'link').

References

• Puzzle Cyclopedia, Nikoli, 2004. ISBN 4-89072-406-0.