A Gentle 7×7 Puzzle Solved with Region Confinement in 19 Steps

This 7×7 board rates as gentle (difficulty score 443). Solving it from scratch takes 19 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, 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 2 touching neighbours.
2. Next, 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.
3. Then, every open cell left in this region sits in column B, so its marker has to land there; that clears every other open cell in the column.
4. After that, place a marker at C4. Region has exactly one open cell left. Placing here clears the rest of row 4, column C, and its region. Placing here also clears its 3 touching neighbours.
5. Now, 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.
6. From there, place a marker at A2. Region has exactly one open cell left. Placing here clears the rest of row 2, column A, and its region.
7. Following that, 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.
8. First, place a marker at G3. Region has exactly one open cell left. Placing here clears the rest of row 3, column G, and its region.
9. Next, 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.
10. Finally, place a marker at B6. Region has exactly one open cell left.

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