An Easy 10×10 Puzzle Solved with Line Confinement in 16 Steps

This 10×10 board rates as easy (difficulty score 583). Solving it from scratch takes 16 logical steps, using 5 techniques: Single cell, Row/column exclusion, Adjacency clear, Region confinement, Line 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, every open cell left in this region sits in row 10, so its marker has to land there; that clears every other open cell in the row.
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 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.
5. Now, every open cell in column A belongs to the same region, so that region's marker has to be somewhere in this column; that clears every other open cell in the region.
6. From there, every open cell in column B belongs to the same region, so that region's marker has to be somewhere in this column; that clears every other open cell in the region.
7. Following that, every open cell in column C belongs to the same region, so that region's marker has to be somewhere in this column; that clears every other open cell in the region.
8. First, place a marker at D9. Column 4 has exactly one open cell left. Placing here clears the rest of row 9, column D, and its region. Placing here also clears its 1 touching neighbour.
9. Next, place a marker at C6. Region has exactly one open cell left. Placing here clears the rest of row 6, column C, and its region.
10. Then, place a marker at H8. Region has exactly one open cell left. Placing here clears the rest of row 8, column H, and its region. Placing here also clears its 1 touching neighbour.
11. After that, place a marker at E5. Column 5 has exactly one open cell left. Placing here clears the rest of row 5, column E, and its region.
12. Now, place a marker at J7. Region has exactly one open cell left. Placing here clears the rest of row 7, column J, and its region.
13. From there, place a marker at A4. Row 4 has exactly one open cell left. Placing here clears the rest of row 4, column A, and its region. Placing here also clears its 1 touching neighbour.
14. Following that, place a marker at B2. Region has exactly one open cell left. Placing here clears the rest of row 2, column B, and its region.
15. 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.
16. Finally, place a marker at F10. Region has exactly one open cell left.

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