An Easy 8×8 Puzzle Solved with Paired Regions in 12 Steps
Play this board yourself →A
B
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8

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This 8×8 board rates as easy (difficulty score 674). Solving it from scratch takes 12 logical steps, using 5 techniques: Single cell, Row/column exclusion, Adjacency clear, Region confinement, Paired regions. Every step below is forced: nothing here is a guess.
- First, every open cell left in this region sits in row 8, so its marker has to land there; that clears every other open cell in the row.
- Next, together, two regions have open cells only in columns G and H; with one marker each, those two markers have to fill exactly those two columns, so every other region's open cells there can be cleared.
- Then, place a marker at F8. Region has exactly one open cell left. Placing here clears the rest of row 8, column F, and its region. Placing here also clears its 2 touching neighbours.
- After that, together, two regions have open cells only in columns D and E; with one marker each, those two markers have to fill exactly those two columns, so every other region's open cells there can be cleared.
- Now, together, two regions have open cells only in rows 6 and 7; with one marker each, those two markers have to fill exactly those two rows, so every other region's open cells there can be cleared.
- From there, place a marker at B5. Region has exactly one open cell left. Placing here clears the rest of row 5, column B, and its region. Placing here also clears its 3 touching neighbours.
- Following that, place a marker at C7. Region has exactly one open cell left. Placing here clears the rest of row 7, column C, and its region.
- First, place a marker at E6. Region has exactly one open cell left. Placing here clears the rest of row 6, column E, and its region.
- Next, place a marker at D1. Region has exactly one open cell left. Placing here clears the rest of row 1, column D, and its region.
- Then, place a marker at H4. Row 4 has exactly one open cell left. Placing here clears the rest of row 4, column H, and its region.
- After that, place a marker at G2. Region has exactly one open cell left. Placing here clears the rest of row 2, column G, and its region.
- Finally, place a marker at A3. Region has exactly one open cell left.
The key move here was Paired regions. Once you can spot that, this board falls quickly. ∎