Yajilin Rules and Strategy
Yajilin is certainly one of the rarest of the many puzzles featured here so you may have never seen it before let alone know the rules or how to solve yajilin. We don't have a magazine of yajilin but we do have many other puzzle magazines for you to enjoy!
Take a look at the yajilin puzzle to the right; this may be the first yajilin you've ever come across. The rules are to create a single loop. Some cells in the grid contain numbers and arrows. These numbers indicate how many cells in that direction are to be filled in black. The loop cannot pass through black cells. Black cells cannot touch each other either vertically or horizontally. The loop must pass through every single cell of the puzzle that is not either filled black or contains arrow information. There may be black cells that are not indicated by the arrows.
The rules of yajilin may sound a little complicated, but once you've solved one puzzle you get the hang of them and they are really quite straightforward. So here are some simple yajilin solving tips and strategies for you that can be used to solve the sample puzzle.
First of all, look at the 0--> arrows in the fourth and fifth cells of the first two rows. These tell you that there are no black cells in cells 5 and 6 of those two rows. Now, we know that every cell that is not black or contains information about black cells must be part of the loop. So we can mark a small 'L' in those cells to indicate that the loop must pass through them.
Now we can use the fact that the loop must be able to enter AND exit every cell it goes into to fill in the shape of the loop. You'll soon see that there is only one way the loop can pass around the corner, so you can mark that part of the loop in. For instance, look at the cell to the left of the top 0-->. The loop must enter it from the cell beneath, and exit it via the cell to its right (or vice versa depending which you want to think of as the exit and entry cells). Similarly for the top right corner cell. Since the two ends of the loop cannot join here then the loop must continue vertically straight out of the two cells at the end of row two.
Now let's look at some simple logic to do with the placement of the black cells in yajilin. Look at the first column. We see that the fifth cell in the column tells us there are two black cells above it. Think about the placement of the black cells. If it were in Cell 3 in the column, it would isolate the cell between the 2 and the black cell, so it can't go there, which can be marked with a small 'L'. Similar logic applies to the second cell in the column. This only leaves two cells that can be black (cells 1 and 4 in the column) and they can be marked accordingly. The loop going in and out of the cells between them can be drawn in.
Now let's look at the final row in this yajilin puzzle. We know there are two black cells in this row. We can instantly place one of them: note how the first column in the row does not have both an exit and entry route. This means it must be coloured black. This means the cell next to it must be part of the loop, and it has only one exit and entry route, which can be drawn in straight away as a result. Now how the '1-->' in row five guides the loop underneath it. This leaves only one cell in the final row that could possibly be black, which is the cell immediately to the right of the '2<--' and so it can be marked in there accordingly.
Remember whenever you fill a black cell in yajilin to write a little 'L' in the cells that touch it to remind yourself that the loop must pass into those cells.
This sample puzzle is now almost finished. By remembering that segments of the loop cannot join as they would be isolated from the rest of the loop, and that black cells cannot be adjacent, we can place the black cell in row five. This steers the loop around it, and we're nearly there. All that's left to work out is where the loop joins itself. By remembering again that two black cells cannot touch each other, we realise the two loop ends must come into the centre of the puzzle and meet in the third/fourth cells of row four.
Now print the puzzle off and have a go at solving it without referring back to the strategy. Did you find this yajilin solving guide and rules useful? Post in the forums, we'd love to know what you think.
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Hanjie is a fun puzzle, would you like to try the easy example in this video? You can do so here: Easy Online Hanjie Puzzle
