Shade
A garden path of numbered paving stones. Shade some of them so that no number is left twice in any row or column; shaded squares may not touch side by side, and all the unshaded squares must join up into one path.
How to play Shade
The rules
Shade squares so that no number appears more than once among the unshaded squares of any row or column. Two shaded squares may never touch side by side, only at corners, and all the unshaded squares must form one group, joined side by side. Breaking a rule draws a dashed or dotted outline around the problem and says what is wrong.
How to play
Tap a square once to shade it, twice to circle it (your note that it stays white) and a third time to clear it. Press and hold, or right-click, to circle straight away. On a keyboard, use the arrow keys, then X or 1 to shade, O or 2 to circle, 0 or Backspace to clear, or Space to cycle. Undo takes back one move, and the counter shows how many repeats are left.
Techniques
The square between two equal numbers stays white. Two equal numbers side by side mean every other copy in that line is shaded. Every square next to a shaded one stays white, and a white number shades its twins in the same row and column. A number with no unshaded twin left in its row and column never needs shading. Then watch the path: a square whose shading would cut squares off from the rest stays white.
Levels and daily
About half of the 5×5 puzzles need only the basic steps; the rest also need a cut. Every 7×7 needs at least one cut. Every 9×9 needs at least one short what-if: shading a square, or keeping it white, breaks a rule within a few steps. The daily puzzle is a 7×7, the same for everyone, and changes at midnight UTC.
Questions
What are the rules of Shade?
Shade squares in a grid of numbers so that no number is left unshaded twice in any row or column. Shaded squares may not touch side by side, and all the unshaded squares must stay joined together in one group.
Is this the same as Hitori?
Yes. Shade follows the same rules as the puzzle also known as Hitori. Here the shaded squares are drawn as garden hedge between paving stones, and the puzzles are our own.
Does every puzzle have exactly one solution?
Yes. Every puzzle was checked by a search that found exactly one shading that keeps all three rules, and solved by a step-by-step solver that uses only logical deductions, so you never need to guess.
Any tips for solving it?
Start with two equal numbers that have one square between them, and with equal numbers side by side. Circle the squares next to your shading, then shade the twins of every circled number. When you get stuck, look for a square whose shading would cut the path in two. Hint finds the next step from your position, does it and explains why; if one of your marks is wrong, it clears that first.
Is there a daily Shade puzzle?
Yes. The daily puzzle is a 7×7 that is the same for everyone and changes at midnight UTC. Earlier dailies are under Past dailies.