Alone rules
How to play Alone
Shade cells until every remaining number is unique in its row and column. Shaded cells never share an edge, and the remaining cells stay connected.
Worked example
Use Next to follow each deduction from the starting clues to the finished board.
Shade duplicate numbers so each remaining value is unique in its row and column. Shaded cells cannot share an edge, and clear cells stay connected.
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- Shade duplicate numbers so each remaining value is unique in its row and column. Shaded cells cannot share an edge, and clear cells stay connected.
- The fifth column has three 4s in a row. If the middle 4 were shaded, the two outer 4s would both remain in the column, creating a repeat. Keep the middle one clear and shade the outer two.
- A shade forces the cells above, below, left, and right to stay clear. The purple X marks are clear-cell notes; add them around both shades.
- Those clear notes settle three more pairs. Shade the left 2 in the second row, the left 4 in the third row, and the left 5 in the fifth row. That last shade marks the 2 beside it clear.
- The clear 2 in the fifth row settles the matching pair in the third column. Shade the other 2 in the top row.
- Three more pairs now have one clear copy: the top-row 1s, first-column 6s, and bottom-row 1s. Shade the other copy in each pair.
- Only the bottom pair of 4s remains. Shading the right 4 would cut off the clear 1 between three shaded cells, so shade the left 4. Every row and column is now complete.
Rules
- In the cells you leave clear, no number may repeat in a row or column.
- Shaded cells may meet at a corner, but they cannot share an edge.
- The clear cells must form one group connected by sides.
Common mistake
Removing every duplicate is not enough. A finished board also has no shaded neighbors and no clear cell cut off from the rest.
Controls
Click a cell to cycle empty, shaded, and marker. Markers are notes for cells you want to keep clear.