PUZZLE TECHNIQUES

NONOGRAM SOLVING TECHNIQUES

Nonogram (also known as "Paint By Numbers", "Japanese Crossword", "Griddler", "CrossPix", "Hanjie") is a puzzle where it is necessary to draw an image in accordance with the numbers outside the grid. The image is made up of black and white squares. The numbers indicate how many groups of black squares are in each row or column.

When you have improved your solving skills with the information on this page, than it is time to try our Nonogram puzzles online.

Only solve Griddlers using logic. Here are some solving tips and tricks:

NUMBER OUTSIDE EQUAL TO GRID SIZE

Our Griddler puzzles are 15x15 pixels in size. If there is 1 digit in the border and it equals 15 (= the size of the grid), then you can black out the entire row or column.

If you have a row or column with only digit 0, you can color the entire row or column white.

NUMBER HIGHERR THAN HALF OF THE GRID
OR HALF OF REMAINING SPACE

Our Griddlers have a size of 15x15 pixels. If there is only 1 number in the border and it is greater than or equal to 8, you can apply the technique below.

See how far you can go starting from both directions. You can make the overlapping squares black.

You can also apply this overlap technique with more than 1 digit. In the puzzle below you see 1 box as an overlap for number 8 and 2 boxes as an overlap for number 4.

There is also overlap in the situation below. In the first line you see 5 and 7 started from the left and below that 5 and 7 started from the right. The fourth line shows the overlap. Please note that this only concerns overlapping of the same numbers. Cell 7 does not count, because it is an overlap of 5 and 7.

NUMBERS SEPARATED BY 1 WHITE CELL
EQUAL TO GRID SIZE

An example will immediately make this technique clearer. We know that the size of our grid is 15.

In the 1st column we find the numbers 436. Together this is 13 and with 3 numbers we need at least 2 white separator boxes. This brings the total to 15, which corresponds to the size of the grid. So without a doubt, we can color the value of the numbers in their correct place.

UNREACHABLE PLACES

Sometimes a number is not high enough to reach certain cells. You can make these WHITE.

In our example below we were able to make 2 cells BLACK as an overlap of digit 6 in column 12. If we now look at row 10 and 11, then digit 3 cannot go further than cell 14, so we can make cell 15 WHITE of row 10 and 11.

IS THERE STILL ENOUGH SPACE?

We continue with the example of the previous technique. By making 2 cells WHITE, a special situation has arisen when we look at column 15.

The numbers 333 require at least 2 WHITE cells. Together this is 11. So there is not enough space for the 3 numbers to be above the 2 WHITE cells. One 3 is therefore located under the WHITE cells. Through the overlap technique we can make 2 cells BLACK from these 3.

MAKE COMPLETE

The overlap method allows us to make 7 cells BLACK in column 3.

If we now look at the rows, we can make a part BLACK from row 6 to row 11.

MERGE AND SPLIT

The more cells that are colored in a row or column, the easier it becomes to color the missing cells. Sometimes we are obliged to merge 2 groups of BLACK cells and sometimes they have to be split.

Below an example of merging. The overlap technique gives us a number of BLACK cells in rows 5 and 7. If we now look at column 5, we only need to color 4 cells. So there is only 1 group. So we can make cell 6 of column 5 BLACK.

We also recommend combining techniques and thus making the inaccessible places WHITE.

Below we consider a split situation. Row 6 has first a group of 5 and then 7 cells. There are already two BLACK cells. We can't put them together, because then we get 7. This is too much for the first group. We now know that the first cell belongs to group 5 and the second to group 7.

DISTINGUISH COMPLETE GROUPS WITH WHITE CELLS

When groups are complete, you can distinguish them with 1 WHITE cell from other groups. Placing WIITE cells is as important as finding BLACK cells.

We have found some BLACK cells on rows 2, 3, 4 and 9 by applying the technique overlap. If we now look at the columns, a number of groups have already become complete. We can now distinguish them from other groups with 1 WHITE cell.

CONTRADICTION

With this technique we can definitely make a particular cell WHITE or BLACK, otherwise we have a conflict with numbers from a specific row or column.

In the example below we can make cell R9K3 WHITE. If it was BLACK, then we would get a conflict with the number 24 of row 9. By making this cell WHITE, we get a better view of the position of digit 6 in column 3.