How to play
- Goal
- Fill the grid with 1 through the cell count exactly once, matching every row and column sum.
- How it ends
- A chart is solved when all cells are filled, no number repeats and every border sum matches; there is no loss state.
- Record
- Your first unassisted finish keeps your time for that chart; later plays are practice.
- Fill every cell with a number from 1 through the total cell count. Use each number exactly once across the whole grid.
- Each row must add up to the sum on its right; each column must add up to the sum below it. Printed givens cannot change.
- Border sums may repeat. The numbers inside the grid cannot repeat; there are no Sudoku boxes or extra adjacency rules.
- Choose a cell, then choose its number. The picker also accepts a typed number and Enter or Set, including values 10 through 16. Erase clears the selected editable cell.
- Restart preserves the first clock. Reload preserves an unfinished original attempt and Undo; its resumed finish stays local. Replay starts fresh and preserves your first time.
Controls
| Mouse / touch | Choose a cell, then its number |
|---|---|
| Arrows + Enter | Move and open number choice |
| Space | Place the selected number |
| Delete / Backspace | Erase the selected editable cell with grid focus |
| Z / Y | Undo / Redo |
| Escape | Close a dialog or return to the atlas |
| Controller | D-pad moves; A or X opens number choice; Y erases; shoulders Undo/Redo; B returns; Start settings; Back rules |
Tips for Survo
- Subtract what is known A column needing 8 with a fixed 2 leaves 6 for its other cell.
- Use the unused numbers A row needing 9 may admit only one pair among the numbers still available.
- Cross-check both directions A candidate must fit its row, its column and global uniqueness.
Questions about this game
May a number repeat in another row?
No. Every number is used once across the entire grid.
May two border sums match?
Yes. Only numbers inside the grid must be distinct.
Are there Sudoku boxes?
No. The rules are global number uniqueness, the givens, and the row and column sums.
Can replay improve my first time?
No. Your saved first finish remains unchanged; replay is practice.
All charts are open. Reload retains an unfinished original attempt, Undo and its clock; resumed finishes stay local. Practice starts fresh and preserves your first time.
Watch how to play
About Survo
Balance numbered counters on a lamplit counting folio. The numbers on the right and bottom tell you the total for each row and column.
All 160 original charts are open: forty each at 2×3, 3×3, 3×4 and 4×4. Each has one independently verified answer and a complete logic proof.
Your first finish keeps its time. An uninterrupted verified first solve can claim the named fastest time; replay is practice.
