Learn · Habits
Nine habits that make sudoku feel hard
Almost every “I am bad at sudoku” story is one of these nine habits. None of them is about intelligence, and all of them are fixable this week.
1. Guessing too early
What it looks like: You place a number you cannot justify, then spend ten minutes repairing the damage.
The fix: Before every entry, say the reason out loud: “this cell has one candidate” or “this digit has one home”. If you cannot finish the sentence, do not type the digit.
2. Never writing candidates
What it looks like: You scan the same three cells for two minutes and conclude “there is nothing here”.
The fix: Start pencil marks the moment singles stop appearing. The board is not hiding information from you; it is hiding it in cells you are not annotating.
3. Writing candidates everywhere, forever
What it looks like: Stale candidates make you reject a cell that is actually solvable, and you lose trust in your own notes.
The fix: Clean as you go: every placement removes a candidate from its 20 peers. Our notes mode highlights peers for exactly this reason.
4. Chasing one digit
What it looks like: You spend the whole puzzle looking for 7s and miss that 3s are collapsing everywhere.
The fix: Rotate: after two failed minutes on a digit, switch to a different digit or a different unit type (row → box).
5. Ignoring the box–line relationship
What it looks like: You miss the eliminations that unlock Hard puzzles, because you only look inside units, never across them.
The fix: Ask the cross question: “this digit is confined to one line inside this box — what does that remove outside the box?”
6. Treating “looks right” as proof
What it looks like: A plausible placement that breaks uniqueness costs you the whole solve.
The fix: A legal move has a reason from the technique ladder. “It fits” is not a reason: with 30 clues, dozens of digits “fit”.
7. Restarting instead of backtracking
What it looks like: You lose all your deductions because a wrong branch made the board look broken.
The fix: Use undo (Ctrl/⌘ Z) rather than restart, and keep a rule: never place a digit you would not defend in one sentence.
8. Racing the clock
What it looks like: Speed rewards guessing, guessing produces errors, errors produce the belief that you are bad at sudoku.
The fix: Play untimed for a week. The timer is a scoreboard, not a teacher.
9. Staying at one difficulty forever
What it looks like: You get fast at Easy and never learn anything again — which is exactly the plateau most players describe as “I am stuck”.
The fix: Spend 80% of your time at the level you can finish and 20% one level above. The practice ladder makes this concrete.
What to do next
Pick the one habit above that sounds most like you, and spend one week on nothing else. Then move to the practice ladder so you are playing at the right difficulty while you fix it.