Featured Puzzle: Stone on Stone #1

As you might have noticed by now, I love the various cell-shading puzzles. Today, we’re taking a look at another Nikoli creation – Stostone. In English, it’s generally known as Stone on Stone. Like Heyawake, you must shade cells according to the numbers in the regions, but there are a few unique requirements.

• Regions with a number must contain a single “stone” – an orthogonally contiguous group of shaded cells equal in size to the number.
• Regions with no number must still hold a stone, but the size is unknown.
• Two stones may not share a side across a region border.
• If you imagine all the solution stones “falling,” the resulting stack must be level across the grid. Another way to put it is that the same number of cells must be shaded in every column.