How to solve Mini Sudoku: the quickest way to learn Sudoku
4 min read ·
Mini Sudoku is classic Sudoku shrunk to a 4×4 or 6×6 grid. The rules are exactly the same, but a puzzle takes a minute or two instead of twenty, which makes it the best place to learn how Sudoku thinking works, or to teach it to a child.
This guide starts with the 4×4 grid, moves on to 6×6, and ends with the habits that carry over to full 9×9 Sudoku.
The rules
- 4×4: every row, column and 2×2 box contains 1, 2, 3 and 4 once each.
- 6×6: every row, column and box of 2 rows by 3 columns contains 1 to 6 once each.
- Every puzzle has exactly one solution, so you never have to guess.
Solving a 4×4 grid
A 4×4 grid starts with about 6 digits. With only four numbers to place, two simple checks solve almost every puzzle:
- Last empty cell: if a row, column or box has three digits filled in, the fourth cell takes the missing number.
- Which number fits here? Pick an empty cell and look at its row, column and box together. If three different numbers already appear there, the cell must be the fourth.
Moving up to 6×6
A 6×6 grid starts with about 14 digits, and it's where real Sudoku technique begins. The boxes are 2 rows tall and 3 columns wide, so the grid has two boxes side by side in each band of two rows.
- Scan one number at a time. Choose a number, say 5, and find every 5 on the board. Each one rules out its row, column and box. If a box has only one cell left where a 5 can go, write it in.
- Check the busiest lines. A row or column with four or five digits already is close to finished; see which numbers are missing and where they can go.
- Use notes when you're stuck. Write the small candidate numbers in each empty cell, then remove them as you fill the grid.
Ready for 9×9
Everything you practise in Mini Sudoku is exactly what you'll use on a full grid: scanning a number across boxes is the hidden single, and the "which number fits here" check is the naked single. When 6×6 puzzles start to feel quick, try Easy Sudoku.
Practise
Every Mini Sudoku on Puzzimo is free, with no sign-up. The daily challenge is a 6×6 grid. Notes, undo and hints are built in, and a wrong number counts as a mistake; three mistakes end the round, so it's worth checking before you place a digit.
Frequently asked questions
Is Mini Sudoku good for kids?
Yes. A 4×4 grid uses only the numbers 1 to 4 and takes a minute or two, so children can finish a whole puzzle and learn the rule that each number appears once in every row, column and box.
How are the boxes arranged in 6×6 Sudoku?
Each box is 2 rows tall and 3 columns wide, so there are six boxes: two side by side in each of three bands.
When should I move from Mini Sudoku to 9×9?
When 6×6 puzzles feel quick and you can solve them without notes. The techniques are the same; a 9×9 grid simply has more of everything.