Your First 10×10 Puzzle

Moving from 5×5 to 10×10 nonograms is a real jump. The grid has four times as many cells, clues become more complex, and you’ll need systematic techniques instead of intuition alone. This walkthrough covers the exact process experienced solvers use.

Phase 1: Quick Wins (30 seconds)

Before applying any advanced technique, grab the free information.

Zero clues

Scan every row and column for a clue of 0. Mark every cell in that line with X. In a 10×10 grid, you might find 0–2 zero lines. Each one eliminates 10 cells instantly.

Full lines

Check if any line’s clues add up to 10 (including mandatory gaps). For example:

Clue 10 → fill all 10 cells
Clue 4 5 → 4 + 1 + 5 = 10 → ■■■■○■■■■■
Clue 2 3 2 → 2 + 1 + 3 + 1 + 2 = 9 → not full, but close (1 cell of slack)

Full lines are solved in one step. Process all of them before moving on.

Phase 2: Overlap Method (2–3 minutes)

This is where the real solving begins. For each row and column, calculate how much overlap exists.

Single-block example

Row clue: 7 in 10 cells.

Leftmost position: cells 1–7. Rightmost position: cells 4–10. The overlap is cells 4–7 — those 4 cells are definitely filled.

Formula: overlap = 2 × block_size − row_length = 2(7) − 10 = 4 cells

Multi-block example

Row clue: 3 4 in 10 cells.

Minimum space: 3 + 1 + 4 = 8. Slack: 10 − 8 = 2.

Push everything left: ■■■○■■■■○○. Push everything right: ○○■■■○■■■■.

Compare: cells 3 and 7-8 overlap. Those cells are confirmed filled. The overlap calculation gets more complex with multiple blocks, but the principle is the same — slide the blocks to both extremes and see what’s shared.

Priority order

Process lines by how much overlap they produce. A clue of 8 in 10 cells gives 6 cells of overlap. A clue of 2 gives 0. Skip low-overlap lines and focus on the high-value ones first.

Phase 3: Cross-Reference (ongoing)

Every filled cell or X you place affects two lines — its row and its column. After completing Phase 2, you’ll have scattered filled cells across the grid. Now examine each crossing line to see what new information is available.

Example cascade

Row 3 overlap gave you a filled cell at column 6
Check column 6’s clue — say it’s 2 1
If that filled cell from row 3 is adjacent to another filled cell in column 6, you’ve confirmed part of the “2” block
Now you know where the “2” block boundaries are → mark X on both sides
Those X marks affect other rows → check those rows

This cascade effect is how the middle of the puzzle gets solved. One deduction leads to another, sometimes triggering a chain of 5–10 fills from a single starting point.

Phase 4: Edge Logic

Once the grid is partially filled, look for blocks pinned to edges.

Wall pinning

If cell 1 of a row is filled and the first clue is 3, then cells 1–3 must be the first block. Cell 4 must be X (gap).

Similarly, if cell 10 is filled and the last clue is 2, cells 9–10 are the last block. Cell 8 must be X.

Gap counting

If you have a confirmed X at cell 5 and the clue is 3 2, the block of 3 must fit entirely within cells 1–4 or cells 6–10. If it can’t fit in cells 1–4 (only 4 cells, but you need 3 — it could fit, but maybe other constraints prevent it), it must be in the other segment. This partitioning narrows possibilities dramatically.

Phase 5: Elimination

In the late stages, many cells are filled or marked. Now you’re looking for lines where:

Only one block remains to be placed, and its position is forced
A segment between two X marks has exactly the right size for a remaining block
Filling the remaining cells of a completed line with X

Completed line check

If a line’s clue is 2 3 and you’ve already placed a block of 2 and a block of 3, every remaining cell in that line is X. Mark them all. This is easy to miss in larger grids — make it a habit to count blocks against clues.

Common 10×10 Mistakes

Skipping the X marks: Empty cells are just as important as filled ones. Every X constrains the puzzle further.

Tunnel vision on rows: If you’re stuck on rows, switch to columns. Fresh perspective on the perpendicular lines often reveals what you missed.

Counting errors: In a 10-cell line with clue 3 2 1, double-check your gap assumptions. Miscounting by one cell compounds into wrong fills downstream.

Not re-checking lines: After placing several cells, go back and re-check lines you previously skipped. They might now have enough information to make progress.

Practice at the Right Level

If 10×10 feels overwhelming, make sure you’re comfortable with 7×7 first. At noguelike.com, the dungeon progression naturally scales from 5×5 through 7×7 to 10×10 as you descend floors, so you build skills incrementally rather than jumping to a grid size you’re not ready for.

The 10×10 size is where nonograms start feeling like a genuine mental workout. Master it, and 15×15 and beyond become a matter of patience rather than new skills.