Sudoku Puzzles Extra Hard

For solvers who love variety and on-demand options, our Sudoku Generators hit the spot. You can pick your exact settings—choosing Extra Hard as the difficulty level, along with any of eight grid sizes, from a neat 4x4 up to a sprawling 16x16. If you fancy the classic 9x9 for your advanced logic battles, go for it; if you want to truly test yourself on an even bigger board, feel free to jump to 12x12 or 15x15. These generators are entirely free to use and produce fresh puzzles every time you click the button, so you’re never stuck solving the same grid twice.

One of the main benefits is that you remain in full control. If you notice that Extra Hard is pushing you to your limit on a certain day, you can easily dial it down to Hard or Medium for a break, then bump it right back up when you’re ready for another attempt at the top tier. Meanwhile, if you’re the type of solver who likes exploring different techniques or practicing a specific strategy, these custom-made puzzles are perfect—you can keep generating new boards until you hit a puzzle that lets you flex those advanced methods. From multi-step chain eliminations to complex pattern findings, you’ll have endless opportunities to test your Sudoku prowess at the pinnacle of difficulty.

If lugging around paper just isn’t your style—or if you appreciate the sleekness of solving on a touchscreen—our Digital Sudoku Books for Extra Hard puzzles might be just what you need. Load them onto devices like iPad, reMarkable, Onyx Boox, Kindle, or Supernote, and you’re all set for a challenging logic session whenever and wherever it suits you. Since these are advanced boards, you’ll be glad you can erase and redo notes with a simple tap, rather than having to scratch out scribbles on paper and risk losing track of your earlier deductions.

Many e-ink and tablet interfaces allow you to zoom in for a closer look, circle tricky squares, highlight potential number placements, or switch pen colors to differentiate various candidate lines. That can come in handy when you’re working through multi-layered logic—especially if you suspect a certain row or box holds a hidden pair or a specialized pattern. Plus, with cloud syncing on many devices, you can pause your puzzle halfway, then pick up exactly where you left off on another tablet or e-ink reader. It’s a modern convenience that makes tackling Extra Hard Sudoku a bit more seamless. No need to shuffle papers or worry about losing your place—just open the file and continue your advanced solving from that last pencil mark you left behind.

It might be hard to imagine a 4x4 puzzle labeled “super hard,” but trust me—it’s possible. Since the grid is so small, every single move counts, and there’s often no room for a slip-up. You can’t just glance at a row or column and spot a quick fix; you actually have to be methodical, even though there are only 16 squares in total.

For seasoned solvers who’ve breezed through easier 4x4s, this level can be a fun surprise. Each placement feels meaningful, and any mistake practically screams at you. It’s a puzzle that tests how well you can juggle limited space with almost no freebies. If you like concentrated challenges that don’t take forever, a super hard 4x4 is both intense and fast-paced.

Shifting to a 6x6 board at super hard can be a real eye-opener. Fewer clues mean you’ll probably have to keep tabs on potential digits in each box, row, and column. Just when you think you see an easy number to place, you’ll realize there’s another candidate blocking your path.

Still, that’s half the fun: once you do find that hidden connection or rule out a certain digit, everything starts falling into place. A 6x6 puzzle might look small compared to the classic 9x9, but at this difficulty, it won’t feel small at all—each row might require the same level of focus you’d normally reserve for bigger boards.

You don’t see 8x8 puzzles as often, but when they’re super hard, they can get surprisingly deep. The layout may not have the usual 3x3 boxes, so you have to adapt your scanning strategy. Add in the sparse clues, and you’ll be challenged to search out every little detail.

That sense of unfamiliarity can be refreshing, though. You’ll find yourself approaching each row and column differently than you do with 9x9. It’s like exploring a less traveled path—where every correct digit feels like a small victory on the way to conquering an entirely new puzzle terrain.

A 9x9 super hard puzzle is where Sudoku fans really earn their stripes. You’ll probably recognize more advanced techniques here—like eliminating hidden pairs or carefully checking each 3x3 box for subtle placements. It’s the classic format, just dialed up to a level that leaves little room for guesswork.

That might mean staring at the same corner of the puzzle for a while before the right insight clicks. But once it does, it can unravel half the board in one go, which is an amazing rush. If you’ve dabbled in regular hard puzzles and want to push yourself further, 9x9 super hard is the ultimate test.

The jump to 10x10 is already a step away from “normal,” and tossing in super hard difficulty makes it a real project. You might find digits 1 through 10, or maybe digits plus letters, which can throw off your typical mental shortcuts. There’s often no easy path—just methodical scanning and double-checking each possibility.

But that’s the appeal. You can savor the novelty of a different grid size and the intensity of fewer givens. For puzzle lovers who want something truly off the beaten track (and are prepared to do some serious note-taking), a 10x10 super hard puzzle is like opening the door to a brand-new dimension of Sudoku.

When you see a 12x12 super hard puzzle, your first thought might be, “Wow, that’s a lot of squares!” And you’re right—it can be daunting. Still, for those who enjoy rolling up their sleeves and wading into a detailed grid, it can be endlessly satisfying. You’ll most likely need advanced logic and a patient approach, but each breakthrough feels huge.

Because of its size, you can think of 12x12 as a long-form Sudoku experience. It’s not something most folks solve in a quick coffee break. Instead, it’s the kind of puzzle you might return to over a day or two, gradually knitting together digits until everything clicks. If you’re in it for the long haul, 12x12 super hard can be surprisingly addictive.

Take one look at a 15x15 grid labeled “super hard,” and you might think you’ve stumbled on a never-ending Sudoku. With so many rows, columns, and sub-boxes to handle, expect minimal hints and a whole lot of logic. Most people who attempt this size end up treating it like a multi-day project—chipping away at bits of the grid, running through advanced strategies, and experiencing repeated bursts of progress.

But that’s the fun of it. Each number you manage to place can open up a flurry of new possibilities, making the effort feel totally worthwhile. Yes, it’s demanding, and it requires real dedication, but the payoff is huge. When you finally fill in that last cell, you’ll have completed a puzzle that only a handful of patient solvers dare to tackle.

For the ultimate Sudoku marathon, 16x16 Super Hard stands at the pinnacle. Not only do you have digits (and sometimes letters) from 1 to 16, but the meager clues barely give you a toehold. You’ll be mapping out possibilities for each cell, maybe focusing on one region at a time to avoid getting lost in the grid’s sheer enormity.

To some, that sounds like a headache; to others, it’s the holy grail of Sudoku challenges. Every piece you successfully lock down feels like cracking a mini-puzzle on its own, and the sense of triumph that comes with completing a 16x16 at this level is off the charts. If you love pushing your brain to its limit, you can’t do much better than this giant, meticulously intricate board.