An Easy 10×10 Puzzle Solved with Region Confinement in 13 Steps

This 10×10 board rates as easy (difficulty score 451). Solving it from scratch takes 13 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 column J, so its marker has to land there; that clears every other open cell in the column.
2. Next, place a marker at I1. Region has exactly one open cell left. Placing here clears the rest of row 1, column I, and its region. Placing here also clears its 1 touching neighbour.
3. Then, 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.
4. After that, place a marker at G10. Region has exactly one open cell left. Placing here clears the rest of row 10, column G, and its region. Placing here also clears its 1 touching neighbour.
5. Now, place a marker at E9. Region has exactly one open cell left. Placing here clears the rest of row 9, column E, and its region. Placing here also clears its 2 touching neighbours.
6. From there, 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.
7. Following that, place a marker at C2. Region has exactly one open cell left. Placing here clears the rest of row 2, column C, and its region. Placing here also clears its 2 touching neighbours.
8. First, place a marker at A3. Row 3 has exactly one open cell left. Placing here clears the rest of row 3, column A, and its region. Placing here also clears its 1 touching neighbour.
9. Next, place a marker at B5. Region has exactly one open cell left. Placing here clears the rest of row 5, column B, and its region.
10. 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.
11. After that, place a marker at H7. Region has exactly one open cell left. Placing here clears the rest of row 7, column H, and its region.
12. Now, place a marker at D6. Region has exactly one open cell left. Placing here clears the rest of row 6, column D, and its region.
13. Finally, place a marker at J8. Region has exactly one open cell left.

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