Welcome to HoDoKu, a Sudoku generator/solver/trainer/analyzer

HoDoKu is a sudoku helper written in Java and available in English and German. Generate sudokus in five different and fully configurable difficulty levels. Solve them yourself (with help from HoDoKu's hint system) or let HoDoKu do it for you.

HoDoKu supports many more human style solving techniques than most other programs available (singles, subsets, LCs, fish, wings, uniqueness, coloring, chains, ALS; for details see "solving techniques"). All steps can be highlighted on the grid which makes HoDoKu a great tool for learning as well.

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Normal view
(Skyscraper is visible)
Show solution path
(Nice Loop is visible)
Show summary
(W-Wing is visible)
ColorKu mode
("Active Cell" panel is visible)
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General options Step options Solver options Color options

If you want to practice a specific technique, simple go to "Training Mode", select a technique, and every new generated sudoku will contain that technique. And if you want it, the sudoku will be solved automatically up to the point, where the technique is applicable.

HoDoKu contains a powerful sudoku analyzer: view all available solution steps for a given state and change your solution accordingly. Manage multiple solutions for one sudoku and write the sudoku plus your solutions to disk.

Version 2 has many more features for you: Choose sudokus from HoDoKu's sudoku history (complete with preview), compute for any step, how far it will advance the sudoku towards the solution, sort available steps according to type, cell, candidate or eliminations. And if you absolutely have to "guess", create a savepoint and revert to it, if your guess was wrong.

HoDoKu version 2.2 has been released. It contains a lot of UI tweaks, including a complete new display type (see ColorKu mode) and some bug fixes. For visually challenged people the font size of the whole GUI (including all dialogs) can be changed (not applicable under some Linux variants). Interoperability with other sudoku programs has been increased by adding various text file formats for sudokus.
Many thanks to ddyer and CCV for their contributions to HoDoKu!
HoDoKu version 2.1.3 has been released. It fixes a critical bug, that could prevent HoDoKu from starting.
HoDoKu version 2.1.2 has been released. It is a maintenance release that fixes the backdoor search and some bugs that only affect batch mode. A few GUI tweaks are included as well.
HoDoKu version 2.1.1 has been released. It fixes a bug in the internal caching mechanism that could lead to incorrect steps for Template Set, Template Delete, Brute Force (batch mode only) and Kraken Fish. The display of the selected cells can now be configured to disappear a predefined time after the last selection change.
It has been a while I but HoDoKu version 2.1 is finally out. It includes a rewrite of all internal data structures and solver classes, which makes the solver two to three times faster than version 2.0. The user manual has not been updated yet.
HoDoKu version 2.0.1 has been released.
HoDoKu version 2.0 has been released.
HoDoKu version 1.2.4 has been released.
The solving techniques guide has now been completed.
The first beta version of the solving techniques guide is now available online.
HoDoKu version 1.2 has been released.
User manual is now online.
HoDoKu version 1.1 has been released.
HoDoKu version 1.0 has been released.
HoDoKu version 0.9 has been released. Although the version number starts with "0" it is extensively tested and should run stable.


HoDoKu is open software licensed under the GPLv3.

Copyright © 2008-12 by Bernhard Hobiger
All material on this page is licensed under the GNU FDLv1.3.