Kakuro

1. 1Fill every white square with a digit from 1 to 9. White squares form runs, across and down.
2. 2The number above the diagonal of a black square is the total of the run to its right; the number below is the total of the run underneath. A digit never repeats inside a run.
3. 3Start with the runs that can only be made one way: two squares adding up to 3 are 1 and 2, three squares adding up to 24 are 7, 8 and 9. Where an across run and a down run cross, the square needs a digit both allow.
4. 4The Run sums button lists the sets of digits the two runs of the selected square can still hold. It is free: it explains, it never fills a square.
5. 5Check my work marks the digits that are wrong. A hint fills in one square: it costs a little XP, never time.
6. 6There is a new puzzle every day, the same for everyone: small and easy from Sunday to Tuesday, bigger from Wednesday to Friday, the big grid on Saturday. Every puzzle has one solution and can be solved by logic alone.

Keyboard: arrows to move (they skip black squares), 1 to 9 to write, N for notes, C for the run sums, Backspace to erase, U to undo.