9×9 with split cells · Constraint

Tight Fit Sudoku

Some cells are split by a diagonal slash and hold two digits - the smaller written above the larger; both digits count against the row, column, region and diagonal neighbours.

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An example Tight Fit puzzle: the slashed cells each hold two digits with the smaller above the larger - here 2/7 and 3/8.

Tight Fit Sudoku squeezes two digits into some cells, splitting them with a diagonal slash. In a split cell the smaller digit goes above the larger, and both count as normal digits for their row, column and region - and for the diagonal-neighbour check that gives the variant its bite.

The rule: two digits, smaller on top

Most cells hold one digit as usual. A cell drawn with a slash holds two, written smaller-over-larger. Every row, column and bold region still uses its digits without repeats; and when you check the cells touching a split cell diagonally, both of its digits are in play.

Solving strategy

  • Order is fixed. In a split cell the top digit is always the smaller - that alone often rules out combinations.
  • Both digits constrain. A split cell removes two values from its row, column and region at once.
  • Mind the diagonals. Split cells interact with their diagonal neighbours through both of their digits.

Common mistakes

  • Writing the larger digit on top. The smaller always sits above the larger in a split cell.
  • Counting a split cell as one digit. It contributes two values to its units.
  • Forgetting the ordinary rules. Rows, columns and regions still each need their full set without repeats.

Can I play it here?

Not yet - Tight Fit Sudoku isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile:

Where to play it

Tight Fit Sudoku belongs to the constraint family and runs on 9×9 with split cells. It is not one SudokuStreak generates yet - but the deduction it trains is the deduction every Sudoku runs on.

Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Expert Sudoku leaves 25 of the 81 cells filled, where the beginner tools dry up almost entirely; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.

About Evil Sudoku