Sudoku
Fill the grid with perfect logic
A 9x9 grid shows up partly filled. Every row, every column, and every 3x3 box has to hold the digits 1 through 9 exactly once, with no repeats. Nothing is random and nothing needs guessing: each digit you place cuts the options everywhere it can see, until one arrangement is the only one left.
How to play
Playing Sudoku
- 1
Tap an empty cell to select it, then tap a digit to drop it into that square.
- 2
Keep every digit 1 through 9 appearing exactly once in each row, column, and 3x3 box.
- 3
Leave the starting clues alone; they are fixed and cannot be changed or cleared.
- 4
Work only from digits you can prove; a guessed number ruins cells far from where you placed it.
- 5
Clear a wrong digit and rebuild from the last cell you actually proved.
- 6
Finish when all 81 cells are filled with no repeat in any row, column, or box.
Tactics
Three ways to get better at Sudoku
Crosshatch the common digits
Pick the digit already on the board the most, say six sevens are placed. Cross out every row and column those sevens sit in, and often a box has exactly one open square left.
Hidden singles beat naked ones
A naked single is a cell with one candidate left. A hidden single is a digit with only one home in its row, column, or box. Hidden singles hide better and are where most stalled grids break open.
Use the pointing pair
When a digit's only spots inside one box sit in the same row, that digit must be in that box, so erase it from the rest of the row. Same trick works down a column.
Inside Reel Games
Sudoku in the swipe feed
Sudoku is a thumb flick from whatever you were on a second ago, and the grid draws before your finger leaves the glass. Nothing loads. The whole puzzle runs on the iPhone itself, so a plane seat or a parking garage plays the same as your own couch, and your score syncs to the leaderboard once you are back online. No ad lands between one solve and the next.
Good for a hospital waiting room with no reception.
Next up
Games like this one
They are all in the same app, so trying one costs a swipe.
Minesweeper
Strategy
Clear the board without triggering a mine
2048
Puzzle
Merge tiles to reach the magic number
Hanoi
Strategy
Solve the classic puzzle
Sudoku is one of 47
Free to download, no ads, and the whole library keeps working when your signal does not.