Sudoku-Land as it exists today — HTML, CSS and JavaScript, 5 difficulty levels, a teaching solver — is not the first Sudoku-Land. The site has a longer, rather more eventful history, and it is worth telling.
The domain name sudoku-land.com was registered on 28 September 2005 — right in the middle of sudoku's worldwide popularity wave, which had just exploded across Europe and the United States after its success in Japan. The .fr was taken at the same time, as a precaution, to keep control of the name.
The game itself was built in Flash (Macromedia at the time, before the Adobe acquisition). The site around it ran on PHP, but almost exclusively for includes — a simple way to factor out the header, the footer and the navigation across pages, without duplicating code everywhere.
Here is a video made at the time with Blender, as a 3D animation, introducing the rules of sudoku along with techniques and tips for beginners:
A 3D animation made with Blender back in the Flash era, explaining the rules and techniques of sudoku. Commentary is in French.
Adobe ended support for Flash Player on 31 December 2020, and started blocking Flash content from running outright on 12 January 2021. The major browsers (Chrome, Firefox, Edge, Safari) removed the plugin at roughly the same time.
The result: Sudoku-Land stayed online throughout all those years — the domain name was never dropped — but the game itself became unplayable, overnight, in any up-to-date browser. The site existed, it just no longer worked.
The complete rewrite of the site began in April 2026: not a single line of Flash left, everything in native HTML, CSS and JavaScript, with no dependency on a plugin that can vanish overnight. The 9×9 grids, the Kids/Junior/Junior+ variants, the teaching solver, the animated help, printing, dark mode — everything Sudoku-Land offers today dates from that rewrite.
Twenty years after the domain name was registered, Sudoku-Land never really disappeared — it just went through a long stretch where it existed without being playable. It works again, and better than before.