CageDoku6×6 Sudoku: Rules and Quick Strategy
By Andrew Boyko, developer of CageDoku · Updated
A 6×6 Sudoku is a small, quick version of the classic: digits 1 to 6, six rows, six columns and six boxes that are two cells tall and three cells wide.
The rules
- Every row, column and 2×3 box contains 1 to 6 once.
- In Killer 6×6, cage sums also apply, with digits not repeating inside a cage.
The sum of a region is 21
1 + 2 + 3 + 4 + 5 + 6 = 21, so the 45 rule becomes the 21 rule: every row, column and box adds up to 21, and innies and outies work the same way.
Quick strategy
- Scan rows and columns for the digit with the fewest places left (hidden singles).
- Use boxes: with 2×3 boxes, a digit that fits only in one row of a box is locked into that row.
- In Killer 6×6, 2-cell cages with sum 3, 4, 10 or 11 and 3-cell cages with sum 6 or 15 are unique combinations.
Daily 6×6
CageDoku’s Daily 3 includes a quick 6×6 every day, along with a Killer and a rotating variant, so you can keep a streak in a couple of minutes.
Frequently asked questions
Is 6×6 Sudoku easier than 9×9?
It is smaller and faster, but the same techniques apply, so it is a good way to learn.
Practice it in CageDoku
Free, ad-free Killer Sudoku and seven more variants. Hints name the technique and highlight the cells, so you learn why a digit goes where it goes.