Easy Sudoku
Easy sudoku here means forty clues — forty-one on the occasional grid that will not dig any further — and, on all but about four boards in a thousand, a path from start to finish using naked and hidden singles alone. You will almost never need a pointing pair, a chain, or a guess. If you are stuck on an easy puzzle, a single is very probably sitting somewhere on the board.
New puzzle generates a fresh grid at the level you last chose, Hint fills one square and names the single it used — a naked single if a cell has one candidate left, a hidden single if a digit has one home left in a unit, and otherwise it simply reveals the answer, which happens on about a fifth of hard grids and a third of expert ones. The three-dot menu at the end of the bar holds pencil marks, fill-in-all-marks, check-as-you-go, today’s shared puzzle and the difficulty level.
Your statistics · easy
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- Best streak
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- Best time
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This level
40–41 clues. Naked and hidden singles finish all but a few grids in a thousand — no chains, no guessing.
Keyboard
- Arrows
- Move the selected cell
- 1 – 9
- Enter a digit
- Backspace
- Clear the cell
- P
- Pencil marks on or off
- F
- Full screen
- Clues
- 40–41
- Techniques needed
- Naked and hidden singles, near enough always
- Guessing
- Never required
- Solutions
- Exactly one, verified
What makes a sudoku easy?
Not the number of clues by itself — that is the common misconception. What makes a puzzle easy is that at every point on the way to the solution there is a cell you can fill in with certainty using only the two simplest techniques:
- A naked single: one empty cell in which only one digit is still possible, because its row, column and box have used the other eight.
- A hidden single: one digit that can only go in one place within a row, column or box, even though that cell could in principle hold others.
Forty clues is what the generator aims at; it is not what makes the puzzle easy, and it is worth being straight that the generator does not classify what it produces. What it proves per puzzle is uniqueness, checked after every pair of clues comes out. Singles-only solvability is measured across the level rather than guaranteed per board: on a 1,000-seed sample, 996 easy grids came apart to singles alone and four needed one step more.
How do you solve an easy sudoku?
- Scan for hidden singles box by box. Pick a digit, look at which of the nine boxes still needs it, and see whether the rows and columns already in play leave it only one square.
- Then scan for naked singles. Any cell with eight of the nine digits already among its peers has exactly one answer.
- Repeat. On an easy grid one filled cell almost always creates the next one, and the puzzle unravels in a chain.
- If you get genuinely stuck, use Fill marks. Seeing the candidates written out turns most apparent dead ends into an obvious single.
When should you move up a level?
When you finish easy puzzles without ever having to hunt. Medium is the first level where singles alone start to run out — roughly one grid in ten — and you have to look at how candidates are distributed rather than at individual cells, which is the point where sudoku stops being a search and starts being deduction.
Easy Sudoku questions people ask
- How many clues does an easy sudoku have?
- Forty on nine easy grids in ten, forty-one on the rest, placed in 180-degree rotationally symmetric pairs the way a hand-made puzzle is. The dig stops when no further pair can come out without a second solution appearing, so it does not always land exactly on the target.
- Do you ever have to guess in easy sudoku?
- Effectively never. Every puzzle has exactly one solution, so a certain move always exists, and on a 1,000-seed sample 996 easy grids were solvable with naked and hidden singles alone from first move to last. The remaining handful need one elimination beyond a single — still deduction, still no guess.
- Is easy sudoku good for beginners?
- It is the right place to start, because it teaches the two techniques that every harder puzzle is built on top of. The hint button here names the technique it used rather than just filling the cell in.
- Can an easy sudoku have more than one solution?
- Not here. Uniqueness is checked after every pair of clues is removed — a puzzle with two solutions is not a sudoku, it is a maze.
The full rules of sudoku
This page is one rule set. The complete rules, with worked examples and the questions beginners actually ask, are on how to play sudoku, and every rule set is switchable on the main sudoku page.