QED Logic quod erat demonstrandum

An Easy 6×6 Puzzle Solved with Paired Regions in 8 Steps

6×6 · easy · 8 steps

Play this board yourself →
A
B
C
D
E
F
1
2
3
4
5
6
1
×
×
2×
×
3×
×
×
×
×
×
×
×
×
×
×
×
4
×
×
5×
6×
×
×
×
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This 6×6 board rates as easy (difficulty score 638). Solving it from scratch takes 8 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.

  1. First, every open cell left in this region sits in column F, so its marker has to land there; that clears every other open cell in the column.
  2. Next, together, two regions have open cells only in columns E and D; 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.
  3. Then, place a marker at C2. Region has exactly one open cell left. Placing here clears the rest of row 2, column C, and its region. Placing here also clears its 3 touching neighbours.
  4. After that, place a marker at A1. Row 1 has exactly one open cell left. Placing here clears the rest of row 1, column A, and its region.
  5. Now, place a marker at E3. Row 3 has exactly one open cell left. Placing here clears the rest of row 3, column E, and its region. Placing here also clears its 1 touching neighbour.
  6. From there, place a marker at F5. Region has exactly one open cell left. Placing here clears the rest of row 5, column F, and its region.
  7. Following that, place a marker at D6. Region has exactly one open cell left. Placing here clears the rest of row 6, column D, and its region.
  8. Finally, place a marker at B4. Region has exactly one open cell left.

The key move here was Paired regions. Once you can spot that, this board falls quickly.