Sudoku
- Generates and solves classic and X-Sudoku Problems. Diverse options and an integrated help facility makes this program best of class.
- http://home.arcor.de/clemens-pichl/Sudoku.htm

The Times Sudoku
- Daily sudoku and killer sudoku puzzles from The Times newspaper, London.
- http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/games_and_puzzles/sudoku/

Free OnLine Sudoku
- Over 200000 sudoku puzzles to play or print for free. No registration needed however you can play a rank game if you register.
- http://www.gosudoku.eu

One Sudoku - one day, one sudoku
- Daily international competition - charts by countries and by users
- http://www.one-sudoku.com

SuDoKu-Cracker
- The SuDoKu-Cracker only creates puzzles with a "unique solution". The built-in Sudoku-generator has six different levels of difficulty and can generate many (millions) different puzzles. All puzzles can be printed, saved and opened again.
- http://www.ksaw.no/sudoku?l=en

Automatic Sudoku solver
- Web-based application for automatic Sudoku solving. After setting a part of grid the puzzle will be automatically solved.
- http://www.jarek.cz/en/logical-puzzles/sudoku/automatic-solver/

Sudoku Puzzles
- Free daily puzzles with five difficulty levels with their solutions. Also offers guide to solve Sudoku puzzles.
- http://www.sudokupuzz.com

Play Sudoku
- Flash version of the Sudoku game. Also offers solution.
- http://www.play-sudoku.com

Sudoweb
- Free daily puzzles with five difficulty levels. Also offers printable e-book.
- http://www.sudoweb.com

Scanraid LTD Search Technologies
- Sudoku Solver by Andrew Stuart. Shows the logic behind solving sample games square by square.
- http://www.scanraid.com/sudoku.htm

Knight Features
- Publishing syndicate in the UK and Ireland. Offers several variations, including classic, colour, kids, and Sudoku Word.
- http://www.knightfeatures.com/KFWeb/content/features/kffeatures/puzzlesandcrosswords/KF/Sudoku/Sudoku_Classic/sudoku_classic.html

Free Sudoku Puzzle
- Articles on the game, its history, and where to find it online.
- http://www.freesudokupuzzle.net/

Solve My Sudoku
- Solves puzzles based on inputted information.
- http://www.solvemysudoku.com/

The Heebie Su Doku Site
- Offers a glossary of terms, links to puzzles and variants, and tips for solving.
- http://sudoku.toplisted.net/syndicate/feed.php?syndtype=top&syndid=1648

World Sudoku Championship
- Information on the 2006 World Sudoku Championship held in Italy. Includes background information, events, results and FAQ. [English, Italian]
- http://www.wsc2006.com/

SuDokuMate
- SuDokuMate is a SuDoku Helper (not a Solver) that replaces pencil and paper to aid solving.
- http://www.sudokumate.com/sudokumate.asp

Flying Frog Consultancy
- This web page describes a 19-line (769-byte) OCaml program that solves Sudoku puzzles.
- http://www.ffconsultancy.com/free/sudoku/

9x9, 6x6 and Samurai Sudoku
- Offers classic Sudoku and variants, as well as an online solver.
- http://www.sudoku.4thewww.com

Gaby Vanhegan
- Daily and random puzzles at six difficulty levels, Flash and JavaScript solvers, solving techniques and glossary of terms.
- http://vanhegan.net/sudoku/

Puzzle Bus
- Offers a daily puzzle, books, software, and related merchandise. Also offers puzzles for syndication.
- http://www.puzzlebus.com

Prize Sudoku
- Offers competitions for prizes. Traditional Sudoku, Godoku (letters) and Super Sudoku (16x16).
- http://prizesudoku.com/

Yosmany.net
- Offers HTML to add a JavaScript-based puzzle to any site. [English/Spanish]
- http://sudoku.yosmany.net

Grant Gibson
- Offers syndicated puzzles for websites as well as print publications.
- http://www.grantgibson.co.uk/sudoku/

Daily Sudoku
- Offers a different printable puzzle each day. Also includes solutions and FAQ.
- http://www.daily-sudoku.com/

Sudoku Online Solver
- Free online generator, solver, and helper. [English/French/Spanish/Polish]
- http://sudoku.friko.net/

Sudoku Helper
- Free online helper application. Shows options for each square, and allows backtrack, restart, or save.
- http://www.pewterweb.com/main/sudoku/nonform/Sudoku.htm

Universal Press Syndicate
- Offers monochrome and color grids and variations for online and print syndication. Information on syndication as well as an interview with creator David Bodycombe.
- http://www.amuniversal.com/ups/features/sudoku/

Daily SuDoku
- Offers daily printable puzzles of varying difficulties, including Sudoku for Kids. Also offers archive of past puzzles, tool for rendering custom puzzles, FAQ, and books for purchase.
- http://www.dailysudoku.co.uk/

The Sudoku Grandmaster
- Self-styled Grandmaster offers tips on life as Sudoku, humorous claims of achievement, and a daily puzzle.
- http://www.sudokugrandmaster.com/

Dan Rice's Sudoku Blog
- Blog discussing techniques for creating and solving puzzles, including hard puzzles. Also offers a daily puzzle.
- http://sudokublog.typepad.com/sudokublog/

Sudoku Place
- Offers daily puzzle in PDF format. Includes archive, FAQ, and a "dozen" variant.
- http://sudokuplace.com/

Christiaan Olie
- Personal page describing Sudoku, rules, strategies, and offering puzzles to print. [Dutch/English]
- http://familieolie.filternet.nl/sudokuenglish.html

Solving Sudoku
- Step by step guide to solving sudoku puzzles. Goes from basic to advanced techniques.
- http://angusj.com/sudoku/hints.php

Simple Sudoku Solver
- JavaScript brute force solver.
- http://homepage.ntlworld.com/valleyway/solver.html

Information For Beginners
- Collection of printable grids, ordered by difficulty level. Solutions provided. Includes rules and solving methods.
- http://www.forbeginners.info/sudoku-puzzles/

Sudoku-san
- Free daily puzzles with four difficulty levels. Also offers a solving assistant and downloadable e-book collections for purchase.
- http://www.sudokusan.com/

Vegard Hanssen's page
- Offers a database of crafted puzzles, organized by difficulty. Also offers FAQ and forum. [Norwegian/English]
- http://www.menneske.no/sudoku/eng/

Sudoku enumeration
- Several programs in different languages for analyzing possible Sudoku combinations.
- http://www.shef.ac.uk/~pm1afj/sudoku/

Sudoku Addict
- Offers printable grids and solution walkthroughs.
- http://www.sudokuaddict.com/

SudokusWeb.com
- Free daily printable Sudokus. Also offers history, rules, and solving techniques. [English/Spanish/French/Catalan/German/Portuguese]
- http://www.sudokusweb.com/

Hirofumi Fujiwara's Sudoku
- Offers a tutorial for creating puzzles, a Java-based solver, and links to other resources. [English/Japanese]
- http://www.pro.or.jp/~fuji/index-eng.html

The Guardian: So you thought Sudoku came from the Land of the Rising Sun...
- Article by David Smith covering the puzzle's origins as "Number Place" by Dell Puzzle Magazine in New York in the 1970s.
- http://observer.guardian.co.uk/uk_news/story/0,6903,1484328,00.html

BBC News: The puzzling popularity of Su Doku
- Article by Paula Dear. Covers history in Japan and the UK and compares to the Rubik's cube craze of the 80s.
- http://news.bbc.co.uk/1/hi/magazine/4469719.stm

Sky One
- Information on UK-based cellular provider's world-record largest Sudoku puzzle and accompanying contest.
- http://www.skyone.co.uk/programme/pgefeature.aspx?pid=48&fid=129

Minimum Sudoku
- A project collecting Sudoku with the smallest number of givens that are still uniquely solvable. Offers the puzzle for download in text format.
- http://www.csse.uwa.edu.au/~gordon/sudokumin.php

The Guardian: Sudoku fever grips UK newspaper readers
- By Stephen Brook. Article covers how the UK craze got started.
- http://media.guardian.co.uk/site/story/0,14173,1480828,00.html

The Economist: Do you sudoku?
- Article on the puzzle's popularity in the United Kingdom and elsewhere.
- http://www.economist.com/displaystory.cfm?story_id=3992476

Maths Is Fun
- Offers a number of applications and solvers for a variety of platforms. Also offers custom puzzles.
- http://www.mathsisfun.net/puzzles.htm

Wikipedia: Sudoku
- An encyclopedia entry describing the rules, history, strategies and variants of Sudoku. Notes that these are a type of "latin square" which have been analyzed since ancient times.
- http://en.wikipedia.org/wiki/Sudoku

Sudoku Online
- Includes Sudoku tips and strategies as well as a downloadable game and a 3D Sudoku puzzle.
- http://www.sudoku.org.uk/

Sudoku.com
- Includes an overview of how Sudoku is solved, a monthly contest and a downloadable Sudoku game. Also includes a kids section and discussion forums.
- http://www.sudoku.com/

My Days Are Numbered
- An article by Seth Stevenson offering a brief overview of Sudoku.
- http://www.slate.com/id/2119796