Have you conquered 'hard' and 'expert' Sudoku, only to find yourself seeking a genuine challenge? The leap into the world of the hardest Sudoku puzzles is a significant one, demanding advanced techniques far beyond simple logic. This transition requires mastery of strategies like X-Wings, Swordfish, and complex forcing chains, offering a rewarding pursuit for any puzzle enthusiast ready to test their limits.
The problem is that many puzzles labelled 'evil' or 'fiendish' often fail to deliver the brain-melting difficulty they promise. This guide cuts through that noise. We've curated a list of seven of the best sources for consistently challenging and meticulously crafted Sudoku. Our selection ranges from trusted UK newspaper archives and dedicated puzzle apps to print subscriptions designed for the purist.
Whether you want a single, impossibly difficult grid to crack over a weekend or a steady supply of top-tier logical challenges, you will find your next favourite source here. We provide a clear overview of each platform, complete with screenshots and direct links, so you can spend less time searching and more time solving. For those who enjoy the pure logic of placement puzzles, you might also appreciate the strategic challenge of games like Queens Game, which hone the same skills of pattern recognition and logical deduction.
1. The Times Bookshop
For Sudoku purists who appreciate the tactile experience of pen on paper, The Times Bookshop is an essential destination. It serves as the official retailer for The Times’ renowned puzzle books, which have become a benchmark for difficulty in the UK. This isn't a platform for interactive play; instead, it offers meticulously curated collections of some of the hardest Sudoku puzzles available in print, perfect for offline solving.
The bookshop's unique strength lies in its trusted difficulty grading. The "Fiendish," "Super Fiendish," and "Extreme" series are long-running best-sellers, each offering a consistent and genuinely demanding challenge. These are not algorithmically generated puzzles of fluctuating quality but hand-selected challenges designed to test even seasoned solvers.
Navigating The Times' Collection
The website primarily sells paperback volumes, each typically containing over 200 puzzles. New books are released regularly, ensuring a fresh supply of challenges. The user experience is straightforward, focusing on book sales rather than interactive features.
- Pricing: Books are competitively priced, often with discounts available directly from the publisher.
- Shipping: It's ideal for UK-based customers, with frequent offers of free postage and packing over a certain spending threshold.
- Availability: While generally well-stocked, popular volumes can sell out, particularly around holiday periods. It's wise to purchase new releases promptly.
Pros and Cons
| Pros | Cons | | ------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------ | | Trusted Difficulty: Consistent, challenging puzzles from a reputable source. | Print Only: No interactive solving, hints, or solution guides. | | Excellent Value: Large puzzle counts per book often make it more economical than apps. | UK-Centric: Primarily designed for easy shipping within the UK. | | Offline Solving: Ideal for travel or disconnecting from screens. | Stock Fluctuations: Popular editions can go out of stock. |
Website: https://timesbookshop.co.uk
2. The Times Puzzles (app/subscription)
For those who prefer a digital solving experience, The Times Puzzles app is the modern counterpart to their classic print books. This subscription-based service consolidates The Times' entire puzzle portfolio into a single mobile application, offering daily challenges that include some of the hardest Sudoku puzzles from a trusted UK publisher. It's designed for serious solvers who want consistent, high-quality puzzles on the go.
The app’s main draw is its curated difficulty and clean, ad-free interface. Unlike many free apps that rely on algorithms of varying quality, The Times provides expertly vetted "Fiendish" and "Super Fiendish" Sudoku and Killer Sudoku puzzles. The dedicated focus required for these complex challenges can be a fantastic mental exercise; to learn more about this, read up on how to improve concentration and focus.
Accessing The Times' Digital Puzzles
The platform is built around a subscription model, providing daily new puzzles and complete access to a vast archive of past editions. This ensures a virtually endless supply of challenges for dedicated subscribers.
- Access: Entry is paywalled. Users need either a full Times Digital subscription or a separate, puzzle-only in-app subscription to unlock all content.
- Platform: The primary experience is through the dedicated mobile app available for iOS and Android. There is no fully featured desktop web app.
- Content: Beyond Sudoku, the subscription includes Killer Sudoku, crosswords, and other logic puzzles from The Times, offering excellent variety.
Pros and Cons
| Pros | Cons | | -------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------- | | Reliable UK Source: Consistently high-quality, well-edited puzzles from a reputable publisher. | Paywalled Content: Requires a subscription for full access. | | Clean, Ad-Free Experience: No interruptions or distracting advertisements for subscribers. | App-Only Focus: Lacks a comprehensive desktop or web-based version. | | Puzzle Variety & Archive: Access to daily Sudoku, Killer Sudoku, and a massive back catalogue. | No Standalone Purchase: Puzzles cannot be bought individually. |
Website: https://www.thetimes.co.uk/puzzles
3. Cracking The Cryptic
For those who believe they have mastered classic Sudoku and crave a new level of challenge, Cracking The Cryptic (CTC) is a revelation. This UK-based phenomenon, famous for its YouTube channel, has expanded into offering meticulously hand-crafted digital puzzle packs. They are renowned for pushing the boundaries of logical deduction, with a strong focus on Sudoku variants that introduce fascinating new rules and constraints, making them a premier source for some of the hardest Sudoku puzzles for the modern solver.
The unique strength of CTC lies in its puzzle design philosophy. Every puzzle is guaranteed to have a single, logical path to the solution, entirely free of guesswork. Accompanied by video walkthroughs from the creators, Simon Anthony and Mark Goodliffe, these packs don't just challenge you; they teach you advanced techniques, helping you understand how to solve logic puzzles with greater skill.
Navigating The CTC Collection
Puzzles are available primarily as downloadable content (DLC) for their base game on Steam or as standalone packs on mobile platforms (iOS and Android). The user interface is clean, intuitive, and designed for a smooth solving experience.
- Pricing: The model is based on affordable, one-off purchases for individual puzzle packs, providing an ad-free experience.
- Access: Mobile packs are self-contained, while Steam users will often need the base "Cracking the Cryptic" game to play the DLC packs.
- Community: A massive, active community on YouTube and Discord provides support, discussion, and a shared passion for solving.
Pros and Cons
| Pros | Cons | | ------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------ | | Exceptional Quality: Human-designed puzzles with guaranteed logical paths. | Variant-Focused: Fewer pure classic Sudokus compared to variants. | | Educational Content: Video walkthroughs teach advanced solving techniques. | Platform-Dependent: Steam DLC often requires the base game. | | Great Value: Low-cost, one-time purchases for high-quality, ad-free puzzle packs. | Digital Only: Not suitable for those who prefer pen-and-paper. |
Website: https://crackingthecryptic.com
4. Conceptis Sudoku
Conceptis offers a premium, mobile-first experience for solvers looking for professionally curated puzzle collections. Instead of relying on algorithmic generation, Conceptis provides hand-picked classic and variant Sudoku puzzles through clean, ad-free mobile apps. Their catalogue is particularly noteworthy for its "Extremely Hard" difficulty packs, which deliver some of the hardest Sudoku puzzles for dedicated enthusiasts.
The platform's main strength is its specialisation in puzzle packs. Users can purchase specific sets tailored to their preferences, from classic Sudoku to variants like Diagonal, Irregular (Jigsaw), and Mega 16×16. This model ensures that solvers who crave a high-difficulty challenge can directly acquire puzzle sets known for their complexity, without wading through easier content.
Navigating The Conceptis App
The app operates on a pay-as-you-go basis, where users buy puzzle packs to solve. This approach keeps the core experience free of intrusive ads and subscriptions, and a free bonus puzzle is offered each week to keep things fresh. The interface is intuitive, focusing entirely on the solving experience.
- Pricing: Puzzle packs are inexpensive, offering a large volume of high-quality puzzles for a one-off purchase.
- Access: Primarily a mobile experience available on iOS and Android. There is no fully-featured desktop site for interactive solving.
- Availability: Packs are purchased per-platform and are not transferable between different app stores (e.g., Apple App Store to Google Play).
Pros and Cons
| Pros | Cons | | --------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------ | | Professional Curation: High-quality, hand-picked puzzles ensure a consistent challenge. | Mobile-Centric: No full desktop version for those who prefer a larger screen. | | Wide Variety: Offers classic Sudoku and many complex variants in dedicated packs. | Platform Lock-in: Purchases are tied to a specific app store. | | Ad-Free Experience: A clean, focused interface without disruptive advertisements. | Pay-to-Play Model: The best hard puzzles are behind a paywall. |
Website: https://apps.apple.com/app/id537201666
5. Sudoku.com (Easybrain)
For those who want immediate access to challenging puzzles without any upfront cost, Sudoku.com by Easybrain is one of the most popular digital destinations. This highly accessible web and app platform offers a clean interface and a vast library of puzzles, including dedicated "Evil" and "Extreme" difficulty levels designed to test advanced solvers. It blends the classic puzzle experience with modern digital tools, making it a strong entry point for tackling some of the hardest Sudoku puzzles online.
The platform’s key advantage is its user-friendly design combined with features that support learning. Unlike print-only options, Sudoku.com provides interactive assistance like notes, hints, and error checking, which can be invaluable when you're stuck on a particularly complex puzzle. This makes it an excellent environment for both seasoned players and those looking to improve their skills, positioning it as one of the best brain-training games available.
Navigating Sudoku.com's Features
The website allows users to jump straight into an "Evil" or "Extreme" puzzle with a single click. The experience is enhanced by daily challenges, event puzzles, and robust progress tracking that monitors your solve times and completion streaks.
- Pricing: The core puzzle-solving experience is free, supported by advertisements. A premium subscription is available to remove ads and unlock additional features.
- Accessibility: Puzzles are available instantly on the web or through dedicated iOS and Android apps, allowing for seamless play across devices.
- User Interface: The design is clean and intuitive, focusing on the puzzle grid with helpful tools readily available but not intrusive.
Pros and Cons
| Pros | Cons | | ------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------- | | Immediate, Free Access: No-cost entry to its most difficult puzzle categories. | Inconsistent Difficulty: Community feedback suggests "Evil" puzzles vary in their true expert-level challenge. | | User-Friendly Tools: Integrated hints, notes, and error checks help with tough spots. | Ad-Supported: The free version includes advertisements that may interrupt gameplay. | | Cross-Platform Play: Available on both web and mobile, with progress synchronised. | Premium for Full Experience: Removing ads and unlocking all features requires a paid subscription. |
Website: https://sudoku.com/evil/
6. Web Sudoku Deluxe
For those who enjoy the classic Web Sudoku interface but crave a greater challenge, the paid desktop version, Web Sudoku Deluxe, is the answer. It elevates the familiar online experience by introducing an "Extreme" difficulty level, which surpasses the website's notoriously tough "Evil" puzzles. This version is designed for dedicated solvers who prefer a dedicated desktop application for offline play and advanced printing capabilities.
The key appeal of Deluxe lies in its expanded features beyond the standard website. It offers some of the hardest Sudoku puzzles from the platform alongside unique variants like Sudoku-X and Squiggly Sudoku. The addition of larger grid sizes (12×12 and 16×16) provides a different kind of complexity, testing a solver's pattern recognition and stamina on a much grander scale.
Accessing the Deluxe Experience
Web Sudoku Deluxe is a one-time purchase, providing a downloadable application for Windows or Mac. This model is ideal for users who want to print puzzles in bulk for offline solving, with options to print up to six grids per page.
- Pricing: A single payment grants lifetime access to the software, with no recurring subscriptions.
- Compatibility: The Windows version is broadly compatible, but users should note the Mac version is a 32-bit application and may not be supported on macOS 10.15 (Catalina) or newer.
- User Interface: The interface retains the classic, no-frills design of the original website, which may feel dated to some but offers a straightforward, distraction-free solving environment.
Pros and Cons
| Pros | Cons | | ------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------- | | Exclusive 'Extreme' Difficulty: Offers puzzles harder than the website's "Evil" tier. | Outdated Mac Version: Limited compatibility with modern macOS releases. | | Offline Play and Printing: Excellent for solving away from an internet connection or on paper. | Dated User Interface: The design is functional but lacks modern polish. | | Puzzle Variety: Includes Sudoku-X, Squiggly, and larger 12×12 and 16×16 grids. | Paid Software: Requires a one-time purchase, unlike the free website. |
Website: https://www.websudoku.com/deluxe.php
7. PuzzleLife Sudoku Extreme 9–10 (isubscribe)
For solvers who crave a consistent, recurring supply of top-tier challenges delivered directly to their door, a subscription to PuzzleLife Sudoku Extreme 9–10 is an excellent choice. Available through isubscribe, this UK-based print magazine is specifically curated for experts, featuring only puzzles rated 9 and 10 on the publisher's difficulty scale. This eliminates the need to sift through easier puzzles, guaranteeing a purely high-level experience.
The primary appeal is its laser focus on the hardest Sudoku puzzles in print format. Unlike one-off books, a subscription ensures a steady stream of fresh, difficult grids arrives periodically throughout the year. The platform, isubscribe, acts as a straightforward hub for managing magazine subscriptions, making the process of ordering and renewing simple for UK and international customers.
Navigating the Subscription
The isubscribe website clearly outlines the offer, focusing on the subscription model rather than interactive gameplay. Users can easily see the savings compared to the recommended retail price (RRP).
- Pricing: Subscription prices are transparent, with options for 10 issues per year. The platform often advertises significant savings for new subscribers.
- Shipping: Delivery is available within the UK and internationally, though costs and timings will vary. Be aware that the first issue can take up to 8–10 weeks to arrive.
- Availability: As a regularly published magazine, stock is consistent, but it’s best to subscribe well in advance if you want to start receiving issues promptly.
Pros and Cons
| Pros | Cons | | ------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------ | | Guaranteed High Difficulty: Every puzzle is graded 9–10, ensuring a consistent expert-level challenge. | Print Only: Lacks any digital features like hints, error-checking, or interactive solving. | | Regular Supply: A subscription provides a steady stream of new puzzles throughout the year. | Long Initial Wait: The first delivery can take a considerable time (8–10 weeks) after ordering. | | Clear Pricing: Transparent subscription options with advertised savings. | Subscription Model: Less flexible than buying individual books or using a free online platform. |
Website: https://www.isubscribe.co.uk/PuzzleLife-Sudoku-Extreme-9-10-Magazine-Subscription.cfm
Hardest Sudoku: 7-Source Comparison
| Product | Complexity / Setup 🔄 | Resources / Cost ⚡ | Expected Quality ⭐ | Results / Impact 📊 | Ideal Use Cases & Tips 💡 | |---|---:|---:|---:|---:|---| | The Times Bookshop | Low — buy paperback, no tech required 🔄 | Moderate one‑off purchase; UK shipping, occasional discounts ⚡ | ⭐⭐⭐⭐ — reliably hard curated sets | 📊 Strong practice value for advanced solvers; offline only | 💡 Best for print collectors and UK buyers; buy during sales | | The Times Puzzles (app/subscription) | Medium — install app + subscription or Times login 🔄 | Recurring subscription (in-app or Times Digital) ⚡ | ⭐⭐⭐⭐ — well-edited hard puzzles | 📊 High convenience: daily puzzles + archive on mobile | 💡 Ideal for daily mobile practice; paywall tradeoff | | Cracking The Cryptic | Medium — base game + DLC or mobile packs; community resources 🔄 | Low-cost one‑off DLCs; some packs require base game ⚡ | ⭐⭐⭐⭐⭐ — top-tier, expertly tested puzzles | 📊 Excellent for learning advanced techniques with video help | 💡 Great for variant-focused experts; use walkthrough videos | | Conceptis Sudoku | Low — install app and buy packs as needed 🔄 | Pay-as-you-go packs; inexpensive per pack; platform-tied ⚡ | ⭐⭐⭐⭐ — professional curation across many variants | 📊 Broad exposure to hard variants; permanent purchased packs | 💡 Good for variant collectors; purchases not cross-store | | Sudoku.com (Easybrain) | Very low — web/app immediate access 🔄 | Free tier with ads; premium to remove ads/unlock extras ⚡ | ⭐⭐⭐ — accessible but expert difficulty inconsistent | 📊 Easy entry, tracking and hints; variable elite challenge | 💡 Best for quick practice and learning aids; upgrade for ad-free | | Web Sudoku Deluxe | Medium — download/install desktop Deluxe or buy online 🔄 | One‑off purchase; platform-specific installers ⚡ | ⭐⭐⭐ — solid for desktop/print enthusiasts | 📊 Strong printable/offline options; older UI and Mac limits | 💡 Ideal for desktop printing; check Mac compatibility | | PuzzleLife Sudoku Extreme (isubscribe) | Low — subscribe for printed issues; recurring delivery 🔄 | Subscription (10 issues/yr); clear pricing and delivery options ⚡ | ⭐⭐⭐⭐ — expert‑level difficulty (levels 9–10) | 📊 Regular supply of very hard print puzzles for experts | 💡 Best for recurring expert print puzzles; expect initial delivery delay |
Choose Your Challenge and Sharpen Your Logical Edge
You have journeyed through some of the most formidable collections available to the modern puzzle enthusiast, from the classic prestige of The Times to the innovative digital creations of Cracking The Cryptic. We have dissected what makes these puzzles truly difficult, moving beyond simple number-placing to the realm of advanced logical deduction. The key takeaway is that the "hardest sudoku puzzles" are not defined by guesswork but by the intricate and elegant chains of logic required to solve them.
Each source we explored offers a unique pathway to mastering these complex grids. Whether you prefer the tactile experience of a physical book, the daily digital challenge from an app, or the deep dive into hand-crafted puzzle packs, there is a resource perfectly suited to your style. You are now equipped to identify which platform aligns with your solving habits and goals.
Selecting Your Next Logical Gauntlet
Choosing the right source is crucial for consistent improvement and enjoyment. Consider these factors when deciding where to find your next challenge:
- For the Traditionalist: If you value curated, high-quality puzzles with a classic feel, The Times Bookshop and PuzzleLife Sudoku Extreme subscriptions offer a superb, screen-free experience. This path is ideal for those who enjoy the focus that pen and paper provide.
- For the Daily Digital Solver: If you want a consistent challenge integrated into your daily routine, The Times Puzzles app and Sudoku.com provide expertly graded puzzles directly to your device. Their built-in tools like hints and notation make them perfect for on-the-go solving.
- For the Logic Aficionado: If you are driven by the "why" behind every deduction and enjoy exploring new rule sets, Cracking The Cryptic is your ultimate destination. Their video solutions and unique variants offer an educational experience that goes far beyond a simple solve.
- For Variety and Volume: For those who want endless puzzles at their fingertips across a range of difficulties, Conceptis Sudoku and Web Sudoku Deluxe offer vast libraries that ensure you will never run out of brain-teasing content.
Beyond the 9x9 Grid
The skills you hone by tackling the hardest sudoku puzzles - pattern recognition, systematic elimination, and deep logical inference - are highly transferable. You are not just learning to solve a specific puzzle; you are training your brain to approach any complex problem with structure and precision. This analytical prowess is valuable in countless other areas, from professional problem-solving to other logic-based games and hobbies.
Ultimately, the journey is about pushing your cognitive boundaries and experiencing the profound satisfaction of unravelling a seemingly impossible grid. The thrill lies not just in finding the solution but in understanding the beautiful, intricate logic that leads to it. So, select your preferred source, embrace the challenge, and continue to sharpen your mind one cell at a time. The next level of logical mastery awaits.
If the art of constraint-based logic and strategic piece placement captivates you, consider channelling those skills into a new kind of challenge. Queens Game offers a fresh and elegant puzzle experience where you master placing queens on a board so none can attack another, building the same foresight and systematic thinking that defines an expert Sudoku solver. Explore a new dimension of logical gameplay and continue your journey at Queens Game.