A Medium 8×8 Puzzle Solved with Shape Squeeze in 15 Steps

This 8×8 board rates as medium (difficulty score 825). Solving it from scratch takes 15 logical steps, using 6 techniques: Single cell, Row/column exclusion, Adjacency clear, Region confinement, Paired regions, Shape squeeze. Every step below is forced: nothing here is a guess.

1. First, every remaining candidate in this region touches G2, so whichever candidate ends up marked will clear it, and it can be ruled out now regardless of which one wins.
2. Next, 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.
3. Then, 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.
4. After that, every remaining candidate in this region touches E2 and E3 and G3, so whichever candidate ends up marked will clear them, and they can be ruled out now regardless of which one wins.
5. Now, every open cell left in this region sits in row 1, so its marker has to land there; that clears every other open cell in the row.
6. From there, place a marker at H2. Region has exactly one open cell left. Placing here clears the rest of row 2, column H, and its region.
7. Following that, place a marker at F3. Region has exactly one open cell left. Placing here clears the rest of row 3, column F, and its region. Placing here also clears its 2 touching neighbours.
8. First, place a marker at A4. Region has exactly one open cell left. Placing here clears the rest of row 4, column A, and its region. Placing here also clears its 1 touching neighbour.
9. Next, place a marker at G5. Region has exactly one open cell left. Placing here clears the rest of row 5, column G, and its region.
10. Then, place a marker at B6. Region has exactly one open cell left. Placing here clears the rest of row 6, column B, and its region. Placing here also clears its 1 touching neighbour.
11. After that, 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.
12. Now, every remaining candidate in this region touches D8, so whichever candidate ends up marked will clear it, and it can be ruled out now regardless of which one wins.
13. From there, place a marker at C8. Region has exactly one open cell left. Placing here clears the rest of row 8, column C, and its region. Placing here also clears its 1 touching neighbour.
14. Following that, place a marker at E7. Region has exactly one open cell left. Placing here clears the rest of row 7, column E, and its region.
15. Finally, place a marker at D1. Region has exactly one open cell left.

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