How to play YAOKU

Place a digit from 1 to 9 in every white square using the Loose Cards in your tray. Arrowed groups must add up to their clues, and badges must multiply to theirs. Each card is used exactly once.

The rules

1. Fill the white squares

The board is 6 × 6. The top row, the left column, and the centre square are gray clue squares. The other 24 squares are white; each takes one digit from 1 to 9. Bold numbers with a small dot are givens: they are fixed, they count toward every clue, and they never use a card.

2. Arrows add

A gray square shows a number with an arrow. An across arrow (→) adds the white squares to its right; a down arrow (↓) adds the squares below it. A group runs until the next gray square or the board edge, so the centre square splits the middle row and column into two short groups and carries two clues at once. Example: a group of three cells marked 12 → could be 3 + 4 + 5.

3. No repeats inside a group

Digits cannot repeat within one arrowed group. They can repeat anywhere else: in a different group, a different row, or across the centre square. YAOKU has no Sudoku boxes and no whole-row rule.

4. Badges multiply

A small square badge sits on the line between two neighbouring white squares. Read its top-left digit as tens and its bottom-right digit as ones. A badge reading 0/8 means the two cells multiply to 8 (1 × 8 or 2 × 4). A badge reading 4/2 means 42, which with digits 1–9 can only be 6 × 7. The badge does not say which cell gets which factor; crossing sums decide that.

5. Use every Loose Card exactly once

The tray below the board holds one card for every blank white square, and together they are exactly the digits the solution needs. Select a cell and tap a card (or type its digit) to place it; the card leaves the tray. Clear, Undo, or Reset puts it back. Repeated numbers are separate cards, and the tray order is no clue. Card counts are a clue, though: once every 7 is on the board, no other cell can be 7.

Putting clues together

Suppose two neighbours share a 3/0 badge and sit in an across group that must add to 11. The badge narrows the pair to 5 and 6 (5 × 6 = 30), and 5 + 6 = 11 agrees. A crossing down group then tells you which of the two is the 5. When several options remain, use Notes to pencil them in instead of guessing: every YAOKU puzzle has exactly one solution and can be finished by logic alone.

Controls

• Tap or click a white cell, then a card. On a keyboard, type 1–9.
• Arrow keys move between white cells. Backspace clears. N toggles Notes. Ctrl/⌘ Z undoes.
• Check marks placed digits that differ from the solution. Hint points to the next logical step and names the rule, without telling you the digit. Both count as assists.
• Turn on rule highlighting to see repeats, overflowing sums, and broken badges as you play.

The Daily and official results

Three Dailies (Easy, Medium, Hard) are chosen by the server for each America/Chicago calendar day and change at midnight Chicago time, including across daylight-saving changes. Difficulty reflects the hardest logical step a puzzle needs: Easy uses direct steps, Medium needs group combinations, and Hard needs card counting across several groups. These labels are still being tuned with player feedback. Signed-in players can play each Daily once for an official, server-timed result that counts toward the Daily and Weekly Leaderboards. See Help for details.