How to solve this 6×6 logic puzzle

6×6 · steady · 9 steps

This 6×6 board rates as steady (difficulty score 661). Solving it from scratch takes 16 logical steps, using 4 techniques: Single cell, Row/column exclusion, Adjacency clear, Paired regions. Every step below is forced — nothing here is a guess.

First, together, two regions have open cells only in columns 5 and 6 — with one marker each, those two markers have to fill exactly those two columns, so every other region's open cells there can be cleared.
Next, together, two regions have open cells only in columns 3 and 4 — with one marker each, those two markers have to fill exactly those two columns, so every other region's open cells there can be cleared.
Then, together, two regions have open cells only in rows 5 and 6 — 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.
After that, place a marker at row 4, column 4. Region has exactly one open cell left. Placing here clears the rest of row 4, column 4, and its region. Placing here also clears its 3 touching neighbours.
Now, place a marker at row 1, column 5. Column 5 has exactly one open cell left. Placing here clears the rest of row 1, column 5, and its region.
From there, place a marker at row 2, column 3. Region has exactly one open cell left. Placing here clears the rest of row 2, column 3, and its region. Placing here also clears its 1 touching neighbour.
Following that, place a marker at row 3, column 1. Region has exactly one open cell left. Placing here clears the rest of row 3, column 1, and its region.
First, place a marker at row 6, column 2. Region has exactly one open cell left. Placing here clears the rest of row 6, column 2, and its region.
Finally, place a marker at row 5, column 6. Region has exactly one open cell left.

The key move here was Paired regions — once you can spot that, this board falls quickly. ∎