sudokUI › HoDoKu
HoDoKu-compatible ratings, in your browser
sudokUI rates and explains sudoku the way HoDoKu does, with nothing to install. It runs in any browser, on a phone, tablet or computer, and keeps working offline.
What HoDoKu is
HoDoKu is a free sudoku generator, solver, trainer and analyser by Bernhard Hobiger, written in Java and released under the GPLv3. Its technique catalogue and scores became a common reference for rating sudoku difficulty. The latest release, version 2.2, dates from 2012.
What sudokUI shares with it
sudokUI uses HoDoKu’s default score for each technique and its default search order, and rates a puzzle the same way: solve it with the first technique that works at every step, and add up the scores.
The score thresholds for Easy (800), Medium (1000), Hard (1600) and Unfair (1800) are HoDoKu’s as well.
Where they differ
sudokUI is an independent project and is not affiliated with HoDoKu.
It adds techniques HoDoKu does not have, such as 3D Medusa, Chute Remote Pair, Fireworks, Tridagon and Exocet, scored next to their closest relatives, and it leaves out a few of HoDoKu’s rarest, such as Mutant and Kraken Fish. On a puzzle that needs one of these, the solve path and the rating can differ.
sudokUI names eight difficulty bands where HoDoKu has five: Beginner, Tricky and Nightmare are additions.
The same puzzle in both
A puzzle written as 81 characters works in both programs. Paste it into sudokUI’s Import dialog to see its rating, its full solution path and every technique available in any position.