QED Logic quod erat demonstrandum

An Easy 7×7 Puzzle Solved with Region Confinement in 10 Steps

7×7 · easy · 10 steps

Play this board yourself →
A
B
C
D
E
F
G
1
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5
6
7
1×
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2
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4×
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5×
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6
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7
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This 7×7 board rates as easy (difficulty score 444). Solving it from scratch takes 10 logical steps, using 4 techniques: Single cell, Row/column exclusion, Adjacency clear, Region confinement. Every step below is forced: nothing here is a guess.

  1. First, every open cell left in this region sits in row 7, so its marker has to land there; that clears every other open cell in the row.
  2. Next, place a marker at G6. Region has exactly one open cell left. Placing here clears the rest of row 6, column G, and its region. Placing here also clears its 1 touching neighbour.
  3. Then, place a marker at F1. Region has exactly one open cell left. Placing here clears the rest of row 1, column F, and its region. Placing here also clears its 1 touching neighbour.
  4. After that, place a marker at E4. Region has exactly one open cell left. Placing here clears the rest of row 4, column E, and its region. Placing here also clears its 2 touching neighbours.
  5. Now, every open cell left in this region sits in row 2, so its marker has to land there; that clears every other open cell in the row.
  6. From there, every open cell left in this region sits in column C, so its marker has to land there; that clears every other open cell in the column.
  7. Following that, place a marker at D2. Region has exactly one open cell left. Placing here clears the rest of row 2, column D, and its region. Placing here also clears its 1 touching neighbour.
  8. First, place a marker at C5. Region has exactly one open cell left. Placing here clears the rest of row 5, column C, and its region.
  9. Next, place a marker at B7. Region has exactly one open cell left. Placing here clears the rest of row 7, column B, and its region.
  10. Finally, place a marker at A3. Region has exactly one open cell left.

The key move here was Region confinement. Once you can spot that, this board falls quickly. ∎