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Features
Candidate Editing via the keyboard is active
Solving
Solve Cell
Solve Partially
Solve
Puzzle Analysis
Check
Rate Difficulty
Hint
Candidates
Generate
Remove
Puzzle
Save
Seed
Print
Clear
Undo
Samples ( 12393 sample puzzles available )
Samples ...

This solver offers a number of features to help you improve your solving skills and practice solving strategies.

Solve Features

Enter the numbers of the puzzle you want to solve in the grid. You can solve the puzzle completely, partially or solve a single cell using the buttons in the Solving section of the Features block.

Button: Solve Cell
Solves the cell of your choice. Click in the cell you want to solve first, then click this button

Button: Solve
Solves the puzzle completely

Button: Solve Partially
Solves the puzzle partially according to the preference settings. To set the preferences, click on the icon in the main menu at the top of the page.

Helper Features

The solver provides several analysis features which allow you to check if a puzzle is valid, rate the difficulty of a puzzle or get hints on how to solve a puzzle step by step.

Button: Check
Checks if the puzzle is valid, can be solved and has a single solution

Button: Rate Difficulty
Display a difficulty rating for the remaining unsolved cells of the puzzle. Ratings are based on the techniques needed to solve the puzzle logically. Below is the list of ratings and associated solving techniques:

Rating
Solution Techniques
Simple
Naked Single, Hidden Single
Easy
Naked Pair, Hidden Pair, Pointing Pairs
Medium
Hard
XWing, Swordfish, Jellyfish, XYWing, XYZWing

Button: Hint
Request a hint to find the next cell to solve. A hint will either identify a cell which can be solved or a cell or cells where candidates can be removed. If candidates are entered on the grid, those candidates will be used to help provide a hint, otherwise the solver will generate the candidates in the background.
Please Note: If the candidates entered are wrong or incomplete, the solver will not be able to provide a correct hint.

Button: Generate
Generate candidate values for all empty cells

Button: Remove
Removes all candidates from all cells

Checkbox: Edit Candidates
When checked candidates can be edited using the keyboard You can edit candidates using the keyboard or the mouse.

Editing Candidates using the Keyboard
- Click the Edit Candidates checkbox first.
- Click in the cell you want to edit
- Type the candidate number to add it
- Type the candidate number again to remove it
- Type the DELETE Key to remove all candidates in a cell

Editing Candidates using the Mouse
- Click in an empty cell
- Click on the position of a candidate to add it
- Click on a candidate to remove it

Load a saved puzzle into the grid.

Button: Save
Save the puzzle currently displayed in the grid.

Button: Seed
Seed the grid from a pasted character string

Button: Print
Print the contents of the grid

Button: Clear
Reset the grid. Empties all cells and removes all candidates

Button: Undo
Revert changes one by one

Free Puzzles

Thousands of free puzzles in varying grades of difficulty are available. Just click on the relevant sample button on the right hand side to load a puzzle of that difficulty to the grid.