On Sudokum, picking a difficulty is picking a page. Open easy and you get easy puzzles; open hard and you get hard ones. Each page draws from its own separate puzzle pool — not just a label stuck on.
This article covers how those pools are built and exactly where each level diverges from the others in practice. Including why Expert sits on its own but is really just a harder slice of Hard.
What Actually Separates the Four Levels
What changes as sudoku gets harder? Fewer clues, sure. But something deeper shifts too: obvious moves stop appearing, candidate relationships get tangled, and past a certain point you simply cannot move forward without pencil marks. On Easy, gut feeling gets you far. On Hard, it runs out fast.
The board opens up fairly quickly. You can get quite far without pencil marks. Good for first-timers and people coming back after a while.
The board won't open itself. You need to revisit the same row multiple times and keep your notes current. Slowing down when you first come from Easy is expected — that's just how this transition feels.
Pencil marks aren't optional here. Miss one candidate relationship and the board can stay stuck for a long time. Speed is irrelevant; what matters is working through the logic in the right sequence.
Drawn from the Hard pool but activating the hard_B subset — puzzles with seventeen to twenty-two clues that break open late. The chains are long and there's almost no margin for error.
What Each Level Actually Feels Like
The differences look small on paper. But once you've worked through a few puzzles at each level, you notice that each one has its own distinct weight.
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Easy
Where you find your footing
Row scanning pays off quickly. Making a mistake and backtracking here won't derail the puzzle. It's the right place to try pencil marks and get comfortable with how they work.
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Medium
One pass isn't enough
You'll need to revisit the same area several times. Reading box and row relationships simultaneously, keeping notes up to date — all of that becomes part of the solve. The intuitive momentum you had on Easy won't carry you here.
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Hard
A hasty move locks everything up
Reading the board at surface level isn't enough. Which cells still hold which candidates, and how those candidates constrain each other — holding all of that in your head without notes is not realistic. One careless entry often becomes a serious problem ten minutes later.
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Expert
The harder end of Hard
It's not technically that different from Hard — it just opens the toughest slice of the pool. You notice the difference immediately: the board gives you nothing in the first few minutes. The Competition Mode uses this level as its baseline. If you want to revisit techniques, the advanced techniques guide is worth reading at this stage.
Which Level Should You Start On?
Starting on Easy isn't a step backward. Once the level choice stops being an ego question, progress comes faster — that might sound obvious, but it's genuinely how it plays out.
The practical test is simple: can you finish the puzzle without hints or guessing? If yes, that level is settled and you're ready to move up. If no, staying put is the smarter call.
If you're playing for the first time
Start on Easy. Work through a few puzzles to get a feel for the game, try out pencil marks, and open the guide if you need it. If Easy really does feel easy, you won't stay long.
When to move to Medium
Once Easy stops tripping you up and the board offers no real resistance, move to Medium. You'll slow down at first — that's normal, and it fades after a puzzle or two.
When does Hard make sense?
If on Medium your notes are getting busy but you still feel in control, it's a reasonable time to open Hard. If the first puzzle leaves you completely lost, don't panic — stay on Medium a bit longer before trying again.
Who is Expert for?
If you can hold the solution chain together in Hard all the way to the end without losing it, you're ready for Expert. If you want the added pressure of the clock, Competition Mode runs at Expert level.
How the Engine Works
On Sudokum, the page URL directly determines the pool: easy, medium, hard, expert. Each page draws from its own dedicated store.
The pool structure is built on three main categories: Easy, Medium, and Hard. Expert is not a separate fourth pool — it's a subset inside the Hard pool, flagged as hard_B. Puzzles with seventeen to twenty-two clues that take a long time to break open fall into that subset. When you load the Expert page, that sub-pool is what activates.
Daily Sudoku runs on its own cycle — Easy, Medium, and Hard. Expert isn't part of the daily rotation. If you want to practice Expert, there's no need to wait for the daily update — just go straight to the Expert page.
Ready to Move Up?
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🟢Easy → Medium
If you've finished several puzzles without hints and without effort, and Easy has stopped challenging you, it's time.
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🟡Medium → Hard
Your notes are getting heavy but you're not losing the thread of your scan? Try Hard. If you're coming apart at the seams, it's not time yet.
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🔴Hard → Expert
If making a mistake on Hard doesn't cause you to lose the entire solution chain, and you want something tougher, Expert is within reach. Finishing Hard cleanly is a good sign; getting there isn't trivial.
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âš«Staying on Expert
Expert puzzles sometimes eat up far more time than expected. That's the point — it's not broken.
Frequently Asked Questions
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It's more than the number of clues. On Easy, clear moves appear early and you can work mostly by intuition. On Hard, those don't exist — what remains in each cell, and how that constrains other cells, simply cannot be tracked without pencil marks.
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There's no shared standard. On one site "Easy" might mean thirty-six clues; on another, twenty-eight. On Sudokum, the route is tied to the page URL: easy, medium, hard, expert — each page has its own pool.
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No. Every Sudokum puzzle has a unique solution, so all of them are solvable through logic. The feeling that you can't move without guessing almost always means a candidate relationship has been missed. On Expert that happens a lot — but the answer is always there somewhere on the board.
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There's no fixed number of days. When a level stops feeling heavy and you can solve a few puzzles comfortably without hints, move on. Spending extra time at a level isn't stagnation — technique builds up gradually.
For technique refreshers, the guide and sudoku strategies are a solid starting point. Once you've moved into Hard and Expert, the advanced techniques become more concretely useful. If you want to add a time element, Competition Mode is right here.