Sudoku365
About Sudoku365
Our Mission
Sudoku365 was created with a simple mission: to provide the best free online Sudoku experience on the web. We believe that Sudoku should be accessible to everyone, load instantly, and work perfectly on any device.
In an era of bloated websites with endless loading spinners and intrusive advertisements, we're committed to the "100/100" philosophy: lightning-fast loading, zero dependencies, and a seamless user experience that scores perfectly on Google PageSpeed Insights.
What Makes Us Different
Pre-Rendered Puzzles for Instant Loading
Unlike most Sudoku websites that generate puzzles with JavaScript after the page loads, we pre-render every puzzle directly into the HTML. This means:
- Puzzles appear instantly, even on slow connections
- Search engines can crawl and index our puzzles properly
- The page works visually even if JavaScript fails
- Zero Cumulative Layout Shift (CLS) for perfect Core Web Vitals scores
Daily Archive - Every Day of 2026
We've generated 1,460 unique puzzles covering every single day of 2026, across four difficulty levels. Each puzzle is:
- Guaranteed to have exactly one unique solution
- Solvable using pure logic without guessing
- Carefully crafted to match its difficulty rating
- Permanently archived so you can solve at your own pace
Printable PDFs for Offline Solving
We know many people prefer solving Sudoku on paper. That's why we offer high-quality printable PDFs with multiple puzzles per page, perfect for:
- Airplane flights and travel
- Classroom activities
- Senior centers and care facilities
- Anyone who enjoys the tactile experience of pencil and paper
Educational Resources
Our comprehensive strategy section teaches techniques from beginner to expert level:
- Basic scanning and naked singles
- Intermediate patterns like hidden singles and naked pairs
- Advanced techniques including X-Wing and Swordfish
- Clear visual diagrams for each technique
Our Technology
Sudoku365 is built using modern web standards with a focus on performance:
Zero Dependencies
No React, no Vue, no jQuery. Just pure vanilla JavaScript with direct DOM manipulation. This keeps our site blazingly fast and our bundle size minimal.
Static Site Generation
Every page is pre-generated as static HTML. This means instant loading, perfect SEO, and the ability to serve our entire site from a CDN.
Optimized Graphics
All icons use SVG format for crisp rendering at any size with tiny file sizes. Our CSS uses CSS Grid for the Sudoku board, ensuring pixel-perfect layouts without heavy frameworks.
Progressive Enhancement
The site works with JavaScript disabled (you can see the puzzle), but JavaScript enhances the experience with interactivity, keyboard shortcuts, dark mode, and game state persistence.
Privacy & Data
We respect your privacy:
- No user accounts required: Start playing immediately without signing up
- Local storage only: Your progress is saved in your browser, never on our servers
- No tracking scripts: We don't use Google Analytics or similar tracking tools
- No cookies: We don't set any cookies (except what your browser uses for local storage)
Read our full Privacy Policy for details.
Contact Us
Have questions, suggestions, or feedback? We'd love to hear from you:
The History of Sudoku
While Sudoku is often associated with Japan, the puzzle actually has American origins. The modern Sudoku puzzle was invented by Howard Garns, an American architect, and first published in 1979 under the name "Number Place."
The puzzle was introduced to Japan in 1984 by Maki Kaji of the puzzle company Nikoli, who gave it the name "Sudoku" (数独), which is short for "Sūji wa dokushin ni kagiru" (数字は独身に限る), meaning "the digits must be single" or "the digits are limited to one occurrence."
Sudoku exploded in worldwide popularity in 2005 when The Times of London began publishing daily puzzles. Today, Sudoku is one of the most popular logic puzzles in the world, appearing in newspapers, magazines, books, and websites in over 100 countries.
Why Play Sudoku?
Mental Exercise
Sudoku provides excellent mental stimulation. Regular puzzle solving has been linked to improved concentration, better problem-solving skills, and enhanced logical thinking abilities.
Stress Relief
Many people find Sudoku meditative and relaxing. The focus required to solve puzzles can help quiet a busy mind and provide a break from daily stressors.
Accessible Challenge
Unlike crossword puzzles that require specific cultural or linguistic knowledge, Sudoku is purely logical. This makes it accessible to people of all ages and backgrounds worldwide.
Skill Development
As you progress from easy to expert puzzles, you'll develop pattern recognition skills and learn sophisticated logical techniques that apply to other areas of problem-solving.
Start Playing Today
Ready to experience the best Sudoku site on the web? Play today's puzzle or browse our complete archive of daily puzzles.