What is Mini Sudoku?
Mini Sudoku is Sudoku on a smaller grid. Fill the empty cells so that every row, column and outlined box contains each digit exactly once.
On Boardsmith, Easy, Medium and Hard use 4×4 grids with the digits 1–4. The optional Expert puzzle uses a 6×6 grid with the digits 1–6. You need logic rather than arithmetic: the digits are labels, not numbers to add up.
Mini Sudoku rules
- Fill every empty cell using the digits for that grid: 1–4 on a 4×4 board or 1–6 on a 6×6 board.
- Use each digit exactly once in every row.
- Use each digit exactly once in every column.
- Use each digit exactly once in every outlined box. The 4×4 boxes are 2×2; the 6×6 boxes are three columns wide and two rows high.
- Keep the starting digits unchanged. Diagonals have no extra rule.
Entering digits and using notes
Select an empty cell, then choose a digit on the keypad or type it on your keyboard. Use Clear to empty a cell, Undo to reverse your last edit, or Reset to clear your entries and notes.
Turn Notes on to mark possible digits without filling the cell. Turn Notes off when you are ready to enter an answer. Notes are for your own reasoning and do not count as filled cells.
Repeated digits in a row, column or box are marked as conflicts. A cell without a conflict is not necessarily correct: it may still prevent you from finishing the rest of the grid.
Mini Sudoku solving tips
Start with rows, columns or boxes that have few empty cells. For each empty cell, rule out digits already present in its row, column and box. If only one digit remains, enter it.
Check the board again after each placement. A digit you have just entered can leave another cell with only one option. The 4×4 difficulties are built around following these forced placements.
On the 6×6 Expert grid, also look for a digit that has only one possible position within a row, column or box, even if that cell has other candidates. Notes can help you track those positions.
If two cells in the same row, column or box can only contain the same two digits, those digits can be removed from the other cells in that row, column or box. Some Expert boards may need this or other candidate-elimination techniques.
The daily Mini Sudoku grids
Boardsmith has daily Easy, Medium, Hard and optional Expert grids, scheduled for midnight UTC. Everyone gets the same puzzle for the same date and difficulty. Each published grid is checked to have exactly one solution and to be solvable using the supported logical techniques, without guessing.
Easy, Medium and Hard all use 4×4 grids. They differ in how many cells you fill and how many rounds of deductions you need. Expert switches to 6×6 and adds reasoning beyond cells with only one possible digit.
Any completed Mini Sudoku puzzle counts towards your daily streak and Mini Sudoku play streak. Complete Easy, Medium and Hard to record a game day and unlock the optional Expert bonus. Expert puzzles completed is a separate cumulative total.
For accounts, saved progress, timers and the daily streak, read the daily puzzle FAQs. See the games page for everything available to play.
Mini Sudoku FAQ
What size are the Mini Sudoku grids?
Boardsmith uses 4×4 grids for Easy, Medium and Hard, with 2×2 boxes and digits 1–4. Expert uses a 6×6 grid, with boxes three columns wide and two rows high, and digits 1–6.
Do diagonals have to contain different digits?
No. In Boardsmith Mini Sudoku, only rows, columns and outlined boxes must contain each digit once. A repeated digit on a diagonal is allowed if it does not break those rules.
Do I ever need to guess?
No. Every published Mini Sudoku grid is checked for a unique solution reachable through logical deductions. If you are stuck, review the remaining candidates and look for a cell or digit with only one possible position.
Does having no conflicts mean my entries are correct?
No. Conflict marks show repeated digits in a row, column or box; they do not check each entry against the solution. A wrong digit can have no immediate conflict and still cause a problem later.
Do notes count as answers?
No. Notes record possible digits. Turn Notes off and enter a single digit to fill a cell. Every cell needs an answer before the puzzle can be complete.
Is Mini Sudoku easier than 9×9 Sudoku?
A smaller grid has fewer cells and digits to track, but difficulty also depends on the deductions required. Boardsmith’s 4×4 grids focus on forced placements; the 6×6 Expert grid needs additional reasoning.