The Guardian's Sudoku 7375 is a hard-level puzzle that challenges even seasoned solvers. This article walks through the solution using logical deduction, avoiding guesswork.
Puzzle Layout and Initial Steps
The grid is a standard 9x9 with given numbers. Start by scanning rows, columns, and boxes for forced placements. For example, in box 1, the number 7 can only go in cell (3,3) due to constraints in row 1 and column 2.
Use pencil marks to track candidates. For Sudoku 7375, many cells have two or three possibilities. Focus on hidden singles where a number appears only once in a row, column, or box.
Advanced Techniques for Hard Puzzles
When basic strategies stall, apply pointing pairs and box-line reductions. In this puzzle, a pointing pair of 5s in row 4 eliminates 5 from other cells in box 5.
Another technique is the X-Wing. For Sudoku 7375, an X-Wing on number 3 in rows 2 and 8 removes 3 from columns 1 and 9 in other rows.
Step-by-Step Solution Path
Start with row 1: given numbers 2, 4, 9. Place 1 in (1,5) after eliminating options. Continue with column 3: missing numbers 1,5,8; 8 goes in (6,3) due to box constraints.
Midway, the puzzle requires a Y-Wing. Cells (4,4), (4,7), and (7,4) form a Y-Wing on numbers 1,6,9, eliminating 9 from (7,7). This unlocks the rest.
Final Solution and Verification
The completed grid has all rows, columns, and boxes summing to 45. Check that each number 1-9 appears once per unit. The solution is unique.
According to The Guardian, hard puzzles like 7375 test logical reasoning and patience. Solving without guessing is satisfying and improves skills.
