Nonogram Overlap Technique (Simple Boxes)
The first move in almost every nonogram is the overlap, also called simple boxes. It needs nothing but a clue and the length of its line. This lesson and the next work on the same 10×10 picture, a sailboat. Rows count from the top and columns from the left.
Step 1 of 5
Slide the block
Row 7's clue is 7, in a row of 10. Push the block as far left as it goes and it covers columns 1 to 7. Push it as far right and it covers columns 4 to 10. Wherever it really sits, it covers columns 4 to 7, the starred cells. They are filled, whatever the rest of the puzzle turns out to be.
Fill the overlap
The cells covered at both ends are the overlap.
Your move
Fill the four cells of row 7 that the block covers wherever it sits.
Two blocks
With more than one block, count the free cells first: the line's length, less its blocks and the one-cell gaps between them. Row 9's clue is 3 4: 3 + 1 + 4 is 8, so 2 cells are free. Each block can slide 2 cells, so each covers its length less 2 wherever it sits: one cell of the 3 and two of the 4.
Your move
Fill the three cells of row 9 that the overlap proves.
When nothing overlaps
Row 4's clue is 4. How many of its cells does the overlap fill?
A perfect fit
Row 10's clue is 2 4 2. How much of the row can you mark right away?
What you learned
- Slide a block to both ends of its line. The cells it covers at both ends are filled.
- Free cells are the line's length less the blocks and the gaps between them. A block fixes its length less the free cells.
- A block no longer than the free space fixes nothing.
- No free cells means the whole line is known.
In this course
Unit 1The rules
Unit 2Solving techniques
- Nonogram Overlap Technique (Simple Boxes)
- Nonogram Edge Technique: Start From the Wall
- Nonogram Technique: Cross Out Finished Lines
- Nonogram Joining and Splitting Techniques
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