Rules

How to play each of the five puzzle types.

Sudoku

Fill every row, column, and 3×3 box with the digits 1–9. No digit may repeat in any row, column, or box. Every puzzle has exactly one solution.

1.Place digits 1–9 in every row so no digit repeats.
2.Place digits 1–9 in every column so no digit repeats.
3.Place digits 1–9 in every 3×3 box so no digit repeats.
4.Use the given clues as your starting points.
5.Every puzzle has exactly one solution.

Start with the digit that appears most often in the given clues.

Kakuro

Fill white cells with digits 1–9 so each horizontal or vertical run sums to the clue shown in the adjacent triangle. No digit may repeat within a single run.

1.Each run of white cells must sum to the clue shown in the adjacent dark triangle.
2.No digit may repeat within a single run.
3.Digits are 1–9 only — zero is not allowed.
4.Dark cells are structural clues — they cannot be filled in.
5.Every puzzle has exactly one solution.

Look for short runs (2–3 cells) with constrained sums — they have very few possible combinations.

Hitori

Shade cells so no number appears twice in any row or column. Shaded cells may not touch each other. All unshaded cells must connect.

1.Shade cells so no number appears twice in any row.
2.Shade cells so no number appears twice in any column.
3.No two shaded cells may touch horizontally or vertically.
4.All unshaded cells must form one connected group.
5.Every puzzle has exactly one solution.

Start with rows or columns that contain three or more copies of the same number.

Nurikabe

Each numbered cell is an island seed. The number shows the island's total size. All water (black) cells must connect. No 2×2 area may be fully black.

1.Each numbered cell is the seed of an island; the number is its total cell count.
2.All black (water) cells must form one connected body.
3.No 2×2 area may be entirely black.
4.Islands cannot touch each other horizontally or vertically.
5.Every puzzle has exactly one solution.

Any cell that cannot logically belong to any island must be water — shade it immediately.

Slitherlink

Draw a single closed loop along the dotted grid lines. The number in each square shows how many of its four sides the loop passes through.

1.Draw edges along the grid lines to form a single closed loop.
2.The number in each square shows how many of its four sides the loop uses.
3.The loop cannot cross or branch — it must be one continuous path.
4.Blank cells (no number) can have any number of loop sides.
5.Every puzzle has exactly one solution.

Squares with 0 have no loop edges; squares with 3 are almost fully enclosed — both are strong starting points.