Ways to play Sudoku: Killer, Jigsaw, Thermo and more
Every variant keeps the classic rule (each row, column and box holds each digit once) and adds one twist. Here are the nine you can play in Ninebloom, with the rule and a first tip for each.
Free in full
Mini 6×6
Each row, column and 3×2 box holds 1 to 6 once. A quick game, and a gentle way to learn singles.
Sums
Killer
Digits in each dashed cage add up to its small number and never repeat in the cage. Full guide and combinations chart →
Extra units
Diagonal
Both long diagonals also hold 1 to 9 once. Tip: the centre cell sits on both diagonals, its row, its column and box 5.
Shapes
Jigsaw
Odd-shaped regions replace the 3×3 boxes, and each holds 1 to 9 once. Tip: a region that pokes into a row often forces digits out of the rest of that row.
Order
Thermo
Along each thermometer, digits strictly increase from the bulb. Tip: a thermometer of length 9 is fully determined: 1 to 9 in order.
Chess
Anti-knight
Two cells a chess knight's move apart never hold the same digit. Tip: every digit you place also rules itself out of the cells a knight's move away, so check those before the usual row, column and box.
Big
Giant 16×16
Each row, column and 4×4 box holds 1 to 16 once, with 10 to 16 shown as A to G. Same techniques, more patience.
Extra units
Windoku
Four shaded 3×3 windows each hold 1 to 9 once as well. Tip: the windows create hidden extra regions between them that also hold 1 to 9.
How they work in Ninebloom
Classic and Mini 6×6 are free in full. Every other way to play has free puzzles to try, and Ninebloom Plus opens the rest, with a new way to play arriving every month or two. Each variant has 200 puzzles per level at Easy, Medium and Hard (Easy and Medium for Giant 16×16), and the hints know each variant's extra rule: a Killer hint counts the cage, an Anti-knight hint the knight's moves.
Every variant shows its rules on the board before your first game.