A Medium 10×10 Puzzle Solved with Shape Squeeze in 22 Steps

This 10×10 board rates as medium (difficulty score 905). Solving it from scratch takes 22 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 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.
2. Next, 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.
3. Then, together, two regions have open cells only in columns A and B; 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 F1 and H1 and F2 and H2, so whichever candidate ends up marked will clear them, and they can be ruled out now regardless of which one wins.
5. Now, every remaining candidate in this region touches I2, so whichever candidate ends up marked will clear it, and it can be ruled out now regardless of which one wins.
6. From there, every open cell left in this region sits in row 3, so its marker has to land there; that clears every other open cell in the row.
7. Following that, together, two regions have open cells only in rows 1 and 2; 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 open cell left in this region sits in row 5, so its marker has to land there; that clears every other open cell in the row.
9. Next, 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.
10. Then, place a marker at G1. Region has exactly one open cell left. Placing here clears the rest of row 1, column G, and its region.
11. After that, place a marker at J2. Region has exactly one open cell left. Placing here clears the rest of row 2, column J, and its region.
12. Now, every remaining candidate in this region touches E5, 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 D5. Region has exactly one open cell left. Placing here clears the rest of row 5, column D, and its region. Placing here also clears its 2 touching neighbours.
14. Following that, 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.
15. First, place a marker at H3. Region has exactly one open cell left. Placing here clears the rest of row 3, column H, and its region. Placing here also clears its 1 touching neighbour.
16. Next, place a marker at I6. Region has exactly one open cell left. Placing here clears the rest of row 6, column I, and its region.
17. Then, place a marker at F4. Region has exactly one open cell left. Placing here clears the rest of row 4, column F, and its region.
18. After that, place a marker at A7. Region has exactly one open cell left. Placing here clears the rest of row 7, column A, and its region. Placing here also clears its 1 touching neighbour.
19. Now, every remaining candidate in this region touches B9, so whichever candidate ends up marked will clear it, and it can be ruled out now regardless of which one wins.
20. From there, place a marker at B10. Region has exactly one open cell left. Placing here clears the rest of row 10, column B, and its region. Placing here also clears its 1 touching neighbour.
21. Following that, 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.
22. Finally, place a marker at E9. Region has exactly one open cell left.

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