Category: Sudoku

Row-column Hidden Single is an important tool for solving Sudoku puzzles. It refers to the combination of row exclusion method and column exclusion method. It uses the “no repetition” rule in Sudoku to determine the position of a number in a row or column by exclusion. Let’s learn this method through some simple examples: Looking at…

The rule of standard Sudoku is to fill in numbers 1-9 in the blank cells, so that each row, each column, and each box contains no duplicate numbers. A box refers to the nine 3×3 square areas enclosed by bold lines.   The Block Hidden Single is one of the most important, basic, and widely…

The rule of standard Sudoku is to fill in each empty cell with a number from 1-9, so that each row, each column, and each 3×3 box contains unique numbers.   In the following figure, the second box already has 8 numbers, and since the numbers in each box can’t repeat, the number in cell…

1-1 The Origin of Sudoku Sudoku is said to be a creation of Euler, but its exact origin is unknown. The author tends to believe that it is the result of the fusion and evolution of various intellectual and mathematical games over a long period of time. 1-2 The Rules of Sudoku Basic rules: Fill…

Please fill in numbers from 1 to 6 in the blank cells in a way that there is no repetition of digits in any row, column, or region; the numbers in gray cells are larger than those in adjacent white cells. Starting with 1, F6=1 follows from the fact that all gray cells except for…

The Chain of Head and Tail Extremes. As shown in the board, the chain is written as follows: H1(1) = A1(1-8) = A6(8) – I6(8) = I4(8-2) = H4(2) => H1<>2, H4<>1 At this point, we find that the chain head and tail are strange: they are not the same candidate numbers. What is the…

Rules: Follow standard Sudoku rules. The hints outside the board indicate the summation value of the longest increasing or decreasing sequence in each row or column. If there are multiple sequences with the same length, the hint indicates the one with the largest sum. In other words, prioritize length first, then sum.

The following puzzle follows the standard Sudoku rules (filling in numbers 1-9 in the blank spaces so that no row, column, or palace has repeated numbers), but it’s not a complete puzzle. However, there’s only one square on the board that can be uniquely determined. Please use logical methods to find it!

Type: 4th Order Smart Grid (KenKen Sudoku) Smart grid (KenKen Sudoku)     A parent asked Topgames for advice because their child is not good at mental arithmetic. Dou Ba will introduce KenKen Sudoku and problem-solving methods below. If the child can practice every day, it will help to improve their mental arithmetic ability while…