Sudoku variant · rules and tips

Sandwich Sudoku

A clue outside the grid is a sum. Find the 1 and the highest digit in that row or column: the 9 on a full grid, the 4 on a 4x4. The digits sitting between those two must add up to the clue.

The 1 and the highest digit are the bread, everything caught between them is the filling, and the bread itself is never counted. Lunch has rarely been so rigorous.

Get it onGoogle PlayPlay Sandwich Sudoku on the web
Professor Cryptic, the owl who teaches in the app
Professor Cryptic explains the rule

The Professor's tips

How do you solve Sandwich Sudoku?

01 / Warm up

Start on a 4 by 4 grid

  • Read the clue as a sum, not as a digit. It tells you what the filling weighs, not how many slices there are.
  • A clue of 0 means the bread is touching: the two crusts sit side by side with no filling at all. A sandwich of pure principle.
  • On a grid this small there are only a handful of arrangements per clue. Write them all out; exhausting the possibilities is quicker than philosophising about them.
02 / Level up

Then try a 6 by 6 grid

  • Find where the bread can sit before you worry about the filling. Fixing the crusts is usually the harder half of the problem.
  • A large clue forces the bread apart towards the edges, because a great deal must fit between the slices.
  • Read the row clues and column clues against each other. Learning where one crust sits from a column often settles a row.
  • The filling is a set, not a sequence. A clue of 5 might be 2 and 3, or a single 5, so consider every decomposition before you commit.
03 / Full size

Move on to a 9 by 9 grid

  • Read the clue as a sum, not as a digit. It tells you what the filling weighs, not how many slices lie inside it.
  • A clue of 0 means the bread is touching: the 1 and the 9 sit side by side with nothing between them.
  • The largest clue possible is 35, which is 2+3+4+5+6+7+8, and it forces the 1 and the 9 to the two ends of the line. The smallest clues push them together.
  • Find where the bread can sit before you worry about the filling. Fixing the crusts is usually the harder half of the problem.
  • Read the row clues and column clues against each other. Learning where one crust sits from a column often settles a row.

The rule, drawn

What does Sandwich Sudoku look like?

  1. Sandwich Sudoku rule illustration, step 1 of 4
  2. Sandwich Sudoku rule illustration, step 2 of 4
  3. Sandwich Sudoku rule illustration, step 3 of 4
  4. Sandwich Sudoku rule illustration, step 4 of 4

Start with a single square

Where can you play Sandwich Sudoku?

Sandwich Sudoku is one of the 17 variants in Cryptic, each with a lesson and unlimited puzzles.

Get it onGoogle PlayPlay on the web