Draw a single closed loop in the grid which doesn't cross (or overlap) itself or thick lines. Every cell (unless entirely surrounded with thick borders) will either be part of the loop or shaded. Arrows indicate how many shaded cells are in that direction (in a straight line up to the edge of the grid), and shaded cells may not be orthogonally adjacent.
First note that the zero requires the loop to use all cells in the left column, and the top/bottom cells are corners so the loop must go in/out of the two remaining edges. Next consider the 1: the implied block cannot go on the bottom row as this would stop the right hand corner from being part of the path, so the block must go directly under the 1. The loop is now forced around the outside of the puzzle and the remaining square must thus be a block.
Yajilin is a Nikoli original. The name is a contraction of "yajirushi", meaning "directing arrow" and "rinku", meaning "link".
Puzzles in this genre