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

This 8×8 board rates as steady (difficulty score 812). Solving it from scratch takes 15 logical steps, using 7 techniques: Single cell, Row/column exclusion, Adjacency clear, Region confinement, Line confinement, Paired regions, Shape squeeze. Every step below is forced: nothing here is a guess.

1. First, every open cell left in this region sits in column H, so its marker has to land there; that clears every other open cell in the column.
2. Next, every open cell left in this region sits in column G, so its marker has to land there; that clears every other open cell in the column.
3. 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 1 touching neighbour.
4. After that, place a marker at E2. Region has exactly one open cell left. Placing here clears the rest of row 2, column E, and its region. Placing here also clears its 2 touching neighbours.
5. Now, every open cell left in this region sits in column A, so its marker has to land there; that clears every other open cell in the column.
6. From there, every open cell in row 1 belongs to the same region, so that region's marker has to be somewhere in this row; that clears every other open cell in the region.
7. Following that, 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.
8. First, every remaining candidate in this region touches H3 and H4, so whichever candidate ends up marked will clear them, and they can be ruled out now regardless of which one wins.
9. Next, place a marker at H5. Region has exactly one open cell left. Placing here clears the rest of row 5, column H, and its region. Placing here also clears its 1 touching neighbour.
10. Then, place a marker at G3. Region has exactly one open cell left.
11. After that, place a marker at D4. Region has exactly one open cell left. Placing here clears the rest of row 4, column D, and its region.
12. Now, every remaining candidate in this region touches B6 and B7, so whichever candidate ends up marked will clear them, and they can be ruled out now regardless of which one wins.
13. From there, 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.
14. Following that, place a marker at B1. Region has exactly one open cell left.
15. Finally, place a marker at A6. Region has exactly one open cell left.

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