Sandwich Sudoku is a variation of classic Sudoku where the numbers outside the grid give extra sum clues. The puzzle still uses a normal 9x9 Sudoku grid, but each row and column may have a clue showing the sum of the digits placed between 1 and 9.
The numbers 1 and 9 act like the two ends of a sandwich. Any digits between them are the filling, and their total must match the clue outside that row or column.
Sandwich Sudoku follows the standard Sudoku rule: every row, column, and 3x3 box must contain the numbers 1 to 9 without repeating. The difference is that the clues outside the grid add a second layer of logic.
For example, if a row has a sandwich clue of 10, the digits between 1 and 9 in that row must add up to 10. The 1 and 9 themselves are not included in the sum.
Classic Sudoku only uses rows, columns, and boxes. Sandwich Sudoku adds outside clues that tell you something about the position of 1 and 9.
A clue of 0 means that 1 and 9 are next to each other, because there are no digits between them. A very large clue means several digits must sit between 1 and 9.
The maximum possible sandwich sum is 35, because the digits between 1 and 9 could be 2, 3, 4, 5, 6, 7, and 8. These numbers add up to 35.
Each difficulty level should teach a different part of Sandwich Sudoku logic. Start with the level that matches your experience.
Sandwich Sudoku is a good choice if you enjoy classic Sudoku and want an extra layer of sum logic. The arithmetic is simple, but the placement of 1 and 9 creates interesting solving decisions.
If you are new to this variation, start with Easy Sandwich Sudoku. If you already understand standard Sudoku and want more challenge, try Medium Sandwich Sudoku.
A Sandwich Sudoku clue shows the sum of the digits placed between 1 and 9 in that row or column.
No. The clue counts only the digits between 1 and 9. The 1 and 9 are the ends of the sandwich.
A 0 clue means there are no digits between 1 and 9, so they must be next to each other in that row or column.
It can be harder because you must follow normal Sudoku rules and also use outside sum clues. Easier puzzles make the sums more direct.
Sandwich Sudoku adds simple but powerful sum clues to the classic puzzle. Find the positions of 1 and 9, read the outside clues carefully, and solve each row and column with logic.