How to solve this 8×8 logic puzzle

This 8×8 board rates as gentle (difficulty score 445). Solving it from scratch takes 21 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, 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.
2. Next, 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. Placing here also clears its 1 touching neighbour.
3. Then, 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.
4. After that, 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 2 touching neighbours.
5. Now, place a marker at E3. Region has exactly one open cell left. Placing here clears the rest of row 3, column E, and its region. Placing here also clears its 1 touching neighbour.
6. From there, place a marker at G6. Region has exactly one open cell left. Placing here clears the rest of row 6, column G, and its region.
7. Following that, every open cell left in this region sits in row 7, so its marker has to land there; that clears every other open cell in the row.
8. First, place a marker at D5. Column 4 has exactly one open cell left. Placing here clears the rest of row 5, column D, and its region.
9. Next, 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.
10. Then, place a marker at B7. Region has exactly one open cell left. Placing here clears the rest of row 7, column B, and its region.
11. Finally, place a marker at C1. Region has exactly one open cell left.

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