This puzzle is part of Monthly Topic Challenge June 2026: Same grid, different execution.
Shade some empty cells in the grid. Two shaded cells cannot share an edge, but they may touch at a corner. Arrows with numbers indicate how many shaded cells there are in the direction of the arrow. Draw a single loop, going horizontally and vertically through centres of cells, which visits every empty cell and none of the shaded or numbered cells. The loop cannot cross itself or branch out.
Final grid:
For this explanation, I'll use light gray for definitely-empty cells, medium gray for definitely-full cells, and dark gray for clues that are now irrelevant.
First, note that we can mark certain edge cells as not being in the loops, i.e. shaded, forcing the cells adjacent them to be unshaded. Then, the loop must pass through those cells, so must pass through the cells adjacent to them:
Next, we can make use of the 0 clues, and also the 2 clues on the right:
There are only two remaining spots for shaded cells on the top row, and one spot where there has to be one on the bottom row, so we can fill those and use that to clear certain cells:
Then, note that there's only one spot for shaded cells to satisfy the 1 clues on the 5th row, and in fact that also forces the 4 clues on the same row:
We can then use that shaded cell to satisfy the 1 clues in the third column, and extend lines a bit:
And then resolve most of the 1 clues in the top half:
Filling out a few more clues, including the 3s on the left and the 5 near the right:
Filling a few more clues allows completing the top right corner:
A few more clues have only one way for their shaded cells to be placed, which allows solving pretty much all the clues:
And then a little more finagling solves the grid!
How I solved it:
Fairly straightforward. I noted first of all that the loop requirement means any dead-ends must be shaded, and any new shaded squares must be placed so as not to leave any dead ends. With no forking permitted, in any intersections such as this one
the loop can only continue in one direction, so the top middle square must be shaded. Paying attention to groups of arrows on the same row or column, such as this:
Any square to the right of the rightmost arrow is also to the right of the leftmost, so all squares in between must be unshaded. With these observations, the solution is rather straightforward. I didn't take intermediary screenshots as there were no particularly obvious distinctive steps in the solution.
