Singles
Cover some of the squares with a purple square, in such a way that:
- no number appears twice in any row or column among the squares left
clear
- no two purple squares are adjacent
- the clear squares form a single connected group (connections
along diagonals do not count).
Controls
On a touch screen, a tap does what a click does, and a long press what a right-click does (more ways to right-click).
Click a square to turn it purple. Right-click it to circle it, marking a square you are sure should stay clear. Keep the button down and drag to do the same to every square you pass over that looked the same as the first.
With the keyboard, the arrow keys move a cursor around the board. Enter does what a click does to the square under it, and Space what a right-click does.
The cursor wraps: an arrow key pressed at an edge of the grid carries it
to the opposite edge.
Either button, or either key, clears a square that is already covered
or circled.
A covered square hides its number. Clicking outside the grid shows
the numbers on the purple squares, and clicking there again hides
them; it is the same setting as the Show numbers on purple
squares preference.
Hints
Hint explains the next step rather than simply making it. It reasons
only from the numbers and your own purple squares and circles, so it
carries on from wherever you are, as long as none of those is wrong; if
one is, it asks you to fix the highlighted mistakes first.
In its words, a purple square is one you have covered, and a
clear square is one that stays uncovered. When a step says a square
must be clear, record that with a circle (right-click); when it must be
purple, click it.
- A ring marks the square the step decides. It is drawn empty: the sentence says whether to shade it or circle it.
- An outline marks the squares the step reasons from, such as two matching numbers one square apart. One you have already shaded or circled is outlined as well, and so is the corner a step keeps from being boxed in.
- Stripes mark the row or column the sentence calls “this row” or “this column”.
A few patterns are worth learning by name:
- A sandwich. Two equal numbers with one square between them: one of
the two must be purple, so the square between them must be clear.
- A touching pair. Two equal numbers side by side: one of them stays
clear, so every other copy of that number in their row or column must
be purple.
- Pairs in neighboring lines. A pair of equal numbers in one row and
another pair in the next, lined up so that covering either of two
squares would force two purple squares side by side. Both must be
clear.
- Corners. Where matching numbers crowd a corner of the grid, some
ways of covering them would leave the corner square with no clear
neighbor, so those are ruled out.
- Keeping the clear squares joined. A square that would cut the
clear squares in two if purple, or seal a clear square off, must
be clear.
Singles parameters
These parameters are available from the ‘Custom type…’ option on the ‘Type’ menu.
- Width, Height
- Size of the grid in squares. A grid under 4 squares both ways has only Easy puzzles. Each must be between 2 and 61.
- Difficulty
- Determine the difficulty of the generated puzzle; see what the names mean.
More help