Lesson:Your First Complete Solve
Now it's your turn. This is an Easy puzzle.
💡 Interactive Board
You can interact with the board on the right at any time during the lesson to test out the concepts being explained.
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💾 Saved locallyAbout This Lesson
Completing your first full Sudoku puzzle is a major milestone. It means you have successfully applied everything learned in the earlier lessons — understanding the grid, the core rules, scanning, and single candidate cells — to take a puzzle from a partially filled board all the way to a complete, valid solution.
The puzzle in this lesson is rated Easy. Easy puzzles are specifically designed to be solvable using only scanning (cross-hatching) and single candidate cells (Naked Singles). No pencil marks are required. The path to the solution is fully logical — every digit you place is forced by the rules, and there is exactly one valid way to complete the board.
Do not rush. Take your time working through the board systematically. Develop the habits that will serve you well as you tackle harder puzzles: work row by row, column by column, box by box; re-scan after every placement; and trust the logic. When a placement seems uncertain, double-check your row, column, and box constraints before committing.
How It Works — Step by Step
Strategy 1 — Start with the most constrained units
Begin with rows, columns, or boxes that already have 6, 7, or 8 digits filled. These are the easiest to complete because so few candidates remain. Filling them creates new constraints for the rest of the grid.
Strategy 2 — Use scanning first
Before touching pencil marks, scan for each digit from 1 to 9 across all nine boxes using cross-hatching. Place every digit you can confirm through scanning alone. This initial sweep often fills 20–35 cells on an Easy puzzle.
Strategy 3 — Then look for single candidate cells
After scanning, examine near-complete rows, columns, and boxes for single candidate cells. Each empty cell in a near-complete unit is a candidate for having only one possible digit.
Strategy 4 — Repeat and iterate
After placing each digit, immediately rescan the affected row, column, and box. New placements cascade — one solution creates two more, which create four more. Keep iterating until the board is complete.
When to Use This Technique
This guided solve is your training ground. Treat it as practice for real puzzles — resist the urge to look for hints unless you are genuinely stuck after trying all scanning and single-candidate approaches.
Worked Examples
Looking at the top row: it has 5, 3, _, 0, 7, _, _, _, _. That means 1, 2, 4, 6, 8, 9 are candidates for the remaining cells. Cross-hatching digit 7 — it is already in this row at column 1. Use column and box constraints to narrow down remaining cells. Work systematically through each digit.
Frequently Asked Questions
What if I get stuck on an Easy puzzle?
Re-scan every digit across every box. Check each near-complete row and column for single candidates. Easy puzzles always have a logical next step available — if you cannot find one, likely a constraint was missed.
Is it okay to guess on an Easy puzzle?
Guessing is never necessary on a well-designed Easy puzzle. If you feel the urge to guess, it means you have missed a logical deduction. Take a step back and re-examine the board from the beginning.
Related Lessons
Ready to test your knowledge? Try applying this technique in our Play Easy Sudoku, Beginner Sudoku lessons or explore Daily Sudoku challenge. Keep training to improve your solve times and master the grid!
Ready to Practice?
Apply this technique on a real puzzle from our daily or practice modes.