SudoCue is Freeware. That may set your expectations a little lower than usual.
Nevertheless, SudoCue is one of the most powerful sudoku solvers currently available, and it has many features that
you will fail to find in any other sudoku program.
Key features in a sample screenshot.
Here is a list of the most prominent program features. New ones are added as you are reading this.
Join the user forum and you can help decide what will be added next.
Very complete set of advanced techniques implemented in the solver:
Easy to recognize Last Digit and Full House singles
Naked Singles, Hidden Singles in rows, columns, boxes and extra groups for variants
Unlocked Singles, using a Pointing Pair to find a Hidden Single
Locked Pairs and Triples
Locked Candidates (Line-Box interactions) types 1 and 2
Naked and Hidden pairs, triples and quads
X-Wing, Swordfish and Jellyfish
Remote Locked Pairs
Aligned Pair Exclusions (APE)
Sue De Coq (2-Sector Disjoint Subsets)
XY-Chains (simple Forcing Chains)
Coloring, Multi-Coloring. Color Trap, Wrap and Wing.
Empty Rectangles (ER) or Hinge
Uniqueness Tests 1 through 4
BUG (Bivalue Universal Grave) +1
Finned X-Wing, Swordfish and Jellyfish
Sashimi X-Wing, Swordfish and Jellyfish
Almost Locked Sets (ALS-XZ rule)
3D Medusa Coloring. Trap, Wrap, Bridge and Complex. Finds all Double Implication Chains
Nishio (a.k.a. templates) catches all single digit patterns
Tabling, a.k.a. Forcing Nets
Dancing Links (DLX) backtracking solver
New techniques are added in each release
Helper with a variety of tools:
Focus on a single digit, dims other digits
Draw cross-hatching lines for a cell of all cells for a single digit
Watch candidates for a single digit, disable or enable them
Watch candidates for multiple digits, with OR & AND relationships
Color candidates for a single digit, with upto available 14 colors
Show marks or small digits for remaining candidates
Peer filtering, focuses your attention to cells that affect the selected cell
Ultracoloring for individual candidates, unique feature!
Supports several Sudoku variants (the program can also generate these variants)
Disjoint Groups (Sudoku-DG)
Center Dot Sudoku
Customizable User Interface
Context menu for quick placement or elimination
Multiple cell selection to eliminate several candidates simultaneously
Select one of the 8 themed screen styles, or use a classic Windows interface
Select your own colors for each screen item
Select one of 5 grid sizes. All screen elements are adapted to fit the size
Choose your preferred coordinate system
Select format for copying sudoku grids
Select style and arrangement of pencilmarks
Minimize to system tray when the boss enters the room
Interactive solver log, featuring:
Detailed report of human-style solver trail
Copy log to clipboard
Select log entry and involved cells are highlighted
Smart hints from the log, current progress. Candidates and groups are highlighted to illustrate the hint.
Step solving assistance helps you learn the game
Solve from here option to show how to sover the remaining puzzle
Vague hint feature
Many input and output possibilities
Copy from and to clipboard, givens, filled cells or all candidates
Open from file, save to file. Many formats supported, with extended properties
Open and browse through large sudoku collections in a single file
Get daily sudokus from several websites
Generate a random puzzle
Choose between 9 types of symmetry or let the program select a random symmetry type
Define and name 5 custom difficulty levels for the generator
Optimizer will make an existing easy sudoku more difficult by removing unnecessary clues
Optimizer can keep the symmetry intact
Guaranteed minimal or symmetrical minimal puzzles are the result
Sudoku analyzer shows you techniques needed and rating
Detailed step analyzer showing the order of techniques
Total rating score, solving path width and number of steps
Count of every solving technique required to complete the puzzle
Useful if you want to know what to look for, without a direct hint
Sudoku scrambler makes a puzzle unrecognizable, but solvable in the same way, unique feature!
Canonicalize Sudokus to detect scrambled equivalents. unique feature!
Intensive support through this website and the user forum
This is no abandonware: New releases still coming your way, with improvements and new features