Find certain cells with overlap
Place a clue group mentally at its earliest legal position, then at its latest. Any cells covered in both layouts must be filled. For a run of 7 in a line of 10, the earliest layout covers cells 1–7 and the latest covers 4–10, so cells 4–7 are guaranteed.
Multiple groups require their minimum one-cell gaps. Build the earliest complete arrangement from one edge and the latest complete arrangement from the other. Compare the positions of the same group, not unrelated filled areas, because clue order never changes.
- 01Choose a line whose clue groups use most of the available cells.
- 02Lay out every group as early as the clues and existing marks permit.
- 03Lay out the same groups as late as permitted.
- 04Fill cells shared by both layouts and recheck crossing lines.
Anchor runs against edges and crosses
When a filled cell lies close to an edge, a group may be forced to extend toward that edge. If a line begins with clue 5 and cell 3 is filled, the first run must cover cell 3; its possible starts are limited, often producing more overlap. A cross acts like a local edge because no group can pass through it.
Respect clue order when choosing which group owns a filled cell. A mark near the start of a line may still belong to a later group if earlier groups fit before it. Test complete legal layouts before extending a run beyond what the evidence supports.
Close completed runs immediately
Once a run reaches the exact length of its clue, mark the square on each open end with a cross. A completed run of four cannot absorb a fifth filled cell. Those boundary crosses separate neighboring clues and may turn the remaining part of the line into a smaller independent problem.
If all groups in a line are accounted for, cross every other square and mark the line complete. This is one of the safest ways to create progress because each new cross constrains a perpendicular clue without changing any filled group.
Exclude spaces that cannot fit a clue
Crosses divide a line into segments. Compare each unresolved clue with the length of each segment: a run of 6 cannot occupy a space of 5, so that segment may belong only to a smaller group or may be empty. Preserve clue order while assigning possible segments.
A partial filled run also sets a minimum requirement. If a segment cannot extend that run to any remaining clue length, one of your assumptions is wrong or a boundary square can be crossed. Work from legal group placements rather than treating isolated filled cells independently.
Build a no-guess solving loop
Use a fixed loop: solve full lines, apply overlap, close exact runs, inspect edge anchors, exclude undersized spaces, then switch orientation. Revisit lines affected by every new mark. A technique that yields only crosses is still valuable because crosses create the boundaries other lines need.
If you are stuck, audit rather than speculate. Confirm clue order, count each run, verify its boundary crosses, and compare earliest and latest layouts again. Clever Pause's hints identify a supported next deduction, and its published clue sets are verified by a solver that does not rely on guesses.
Common questions
What is the overlap technique in Nonograms?
It fills cells covered by both the earliest and latest legal positions of the same clue group. Those cells belong to the run in every valid layout.
When can I extend a filled run?
Extend it only when every legal placement of its clue covers the added square. An edge, a cross, or the clue's required length may provide that proof.
Why should I add crosses around a completed run?
Separate clue groups cannot touch. Once a run reaches its exact clue length, adjacent squares must be empty and become useful boundaries for crossing lines.
How do I use a small empty segment?
Compare its length with unresolved clues. Any clue longer than the segment cannot occupy it, but clue order and other segments determine whether every square can be crossed.
Are these techniques enough to avoid guessing?
They cover the core deductions used by Clever Pause's public set. Harder boards combine them across several lines, so the next move may appear far from the area you were studying.