A Medium 7×7 Puzzle Solved with Shape Squeeze in 15 Steps

This 7×7 board rates as medium (difficulty score 828). 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 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.
2. Next, together, two regions have open cells only in rows 4 and 5; 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.
3. Then, 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.
4. After that, 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.
5. Now, every remaining candidate in this region touches F2, so whichever candidate ends up marked will clear it, and it can be ruled out now regardless of which one wins.
6. From there, 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 3 touching neighbours.
7. Following that, 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.
8. First, every remaining candidate in this region touches D4 and D5, 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 E5. Region has exactly one open cell left. Placing here clears the rest of row 5, column E, and its region. Placing here also clears its 1 touching neighbour.
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 C4. Region has exactly one open cell left.
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 D7. Region has exactly one open cell left. Placing here clears the rest of row 7, column D, and its region.
14. Following that, place a marker at B2. 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. ∎