Sudoku & Killer Sudoku

Description

Written exam over 3.5 hours. Includes four sections:  Classic Sudoku Puzzles, Diagonal Sudoku Puzzles, Killer Sudoku puzzles, and KenKen.

Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid (also called “boxes”, “blocks”, “regions”, or “sub-squares”) contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a unique solution.
In KenKen as in Sudoku, the goal of each puzzle is to fill a grid with digits –– 1 through 4 for a 4×4 grid, 1 through 5 for a 5×5, etc. –– so that no digit appears more than once in any row or any column (a Latin square). Grids range in size from 3×3 to 9×9. Additionally, KenKen grids are divided into heavily outlined groups of cells –– often called “cages” –– and the numbers in the cells of each cage must produce a certain “target” number when combined using a specified mathematical operation (either addition, subtraction, multiplication or division). Digits may be repeated within a cage, as long as they are not in the same row or column.

In the event of an equal score, placing will be determined by the time finished.

The format of the 2026 paper is the same as the 2025 paper, which can be found here along with solutions for reference:

MSO Sudoku Questions 2025

MSO Sudoku Solutions 2025