Place clues
- Solutions
- Place a digit to begin
- Difficulty
- Needs one solution
- Clues
- 0
- Moves needed
- -
- Hardest move
- -
- Clue symmetry
- -
- Symmetry guide
- Off
Reference
Clues tab
- Clue symmetry
- The symmetry the clues already have. Its "Guide by" link makes it the symmetry guide.
- Minimal
- Whether every clue is needed. Clues that could go lists each one that can be removed alone; hover to locate it, click to remove it.
- True candidates
- Shows, in each empty cell, every digit that some solution places there.
- Make unique
- Adds clues from one solution until only that solution remains, then removes any it did not need.
- Clues that cut the most
- Single clues ranked by how many solutions each would leave.
- Compare
- Rates the puzzle with each clue that would make it unique added: hardest technique and likely band. Click a result to apply it.
Solve path tab
- Techniques
- Each technique the puzzle needs, easiest first, with its count. Click one to show its first move.
- Moves
- Every move in solving order, coloured by difficulty. Hover to preview the board at that move; click to pin it and read the explanation.
Generate tab
- Random grid
- Fills every cell with a random solved grid.
- Fill in the rest
- Completes one solution of the current clues, to accept or discard.
- Remove clues
- Removes clues at random down to the chosen count while the puzzle stays unique. Tries new orders for up to ten seconds and keeps the fewest reached.
- Locked clues
- Never removed by Remove clues or Make unique. Select clues, then use Lock.
- Pattern search
- Paint the cells that should hold clues (at least 17), then Search finds unique puzzles with clues in exactly those cells. Keep my clues builds around the clues already in pattern cells. Each find is rated in the background; click one to preview it, Load to use it. The list stays, so another find can be loaded instead.
Symmetry and transforms
- Symmetry
- Set under the board. Rings the empty cells the symmetry needs filled, and makes Remove clues, Make unique and pattern painting work in symmetric groups.
- Transform
- Rotates, flips or mirrors the grid, shuffles bands, stacks, rows or columns, or renames digits. The solution count, logic and difficulty are unchanged.
Sharing and saving
- Play
- Opens the puzzle in the Peak Sudoku player in a new tab. Available once the puzzle is unique.
- Share
- Play and edit links, text formats including minlex, an image, and a PDF with the solution.
- Saving
- Automatic. Stored in this browser, or in your account when signed in. The address bar always links back to the puzzle.
- My puzzles
- Every puzzle you are making. Open, start a new one, duplicate or delete.
- Techniques
- Explanations of every technique named in the Solve path are in the technique guide.
Frequently asked questions
- Is the Sudoku Maker free?
- Yes. No account is required and there is no limit on the number of puzzles. Puzzles are saved in the browser, or in your account when you are signed in.
- How is uniqueness checked?
- An exhaustive search runs in the browser after every edit and counts the solutions, up to 10,000. A puzzle marked unique has exactly one solution.
- What are true candidates?
- The digits that appear in at least one solution of the current board. Pencil marks only exclude digits already in a cell's row, column and box; true candidates show what is still possible, and therefore where a missing clue has to go.
- How is difficulty rated?
- The same way as every puzzle in the Peak Sudoku library. A solver limited to human techniques determines the moves required, and the puzzle receives a Peak Score from 1 to 100 and the difficulty band it falls in.
- Can puzzles be shared?
- Yes. Once a puzzle has a single solution it can be shared as a play link, a printable PDF with its solution, or an image. Puzzles made here are not added to the library.
- What is a minimal puzzle?
- A puzzle in which every clue is required: Removing any one of them admits a second solution. The Clues tab lists the clues that could go, and Remove clues on the Generate tab removes them while keeping the puzzle unique.