Sudoku for Beginners: Your First Game, Step by Step

Most Sudoku guides hand you a list of rules and wish you luck. This one plays a game with you. Below is a real Easy puzzle from our own generator - the same board you would be dealt if you started a game right now - and we will work through the opening moves together, one at a time, explaining each as we make it.

You will not need to memorise a single technique. Every move here comes from the rules alone.

The rules, in one sentence

Fill every empty cell so that each row, each column and each 3×3 box contains the digits 1 to 9 exactly once. That is the whole game. Everything else - every technique with a name - is just a faster way of noticing what those three rules already force.

One consequence is worth saying out loud, because it is the thing beginners most often miss: every cell belongs to three regions at once. A digit you write restricts its row, its column and its box, all at the same time.

Our board

Move 1: find where a digit is forced to go

Do not start by staring at an empty cell and wondering what goes in it. Start with a digit and ask where it can still live. Take the 3, and look only at the top-right box.

Here is the reasoning in full. The top-right box needs a 3 somewhere. Its left-hand column already contains a 3 lower down the grid, so no cell in that column can take another one. Its right-hand column contains a 3 as well, so those are out too. That leaves the middle column of the box - and two of its three cells are already taken, by the 6 and the 7.

One empty cell remains, so the 3 belongs there. Not "probably" - the rules leave nowhere else for it to go. This is the move known as a hidden single, and on an Easy board you can win the whole game with it. The scanning that finds it is called crosshatching.

Move 2: the digit you just wrote changes the board

This is the habit that separates players who flow from players who get stuck: after every digit, look at what it just ruled out.

The 3 we placed sits in the top row. That row now has its 3 - which means the top-middle box can no longer put its own 3 in the top row at all. Look at that box: it has exactly two empty cells, one of them in the top row. The top-row one is now blocked, so the 3 must go in the other.

Notice what happened. That second move was not available a moment ago. It became available because of the first one. A Sudoku is a chain, not a list, and this is why re-scanning after each placement is worth more than any technique you could memorise.

Move 3: the easiest move of all

The top-middle box now has a single empty cell left. Whatever digit the box is missing simply goes there - you do not even need to look at the row or the column. Count what the box already holds, and write the one that is absent. It is an 8.

This is a naked single in its simplest form, sometimes called a full house: one cell, one possibility. Once a region is nearly complete it finishes itself, which is why filling one region tends to cascade into its neighbours.

Now keep going

Those three moves are the entire toolkit for an Easy board. Repeat them in this order and the grid will unravel:

1. Pick a digit that appears often and hunt its remaining homes box by box. Digits with many copies already placed are the most constrained, so they fall first.
2. After each placement, re-check its row, its column and its box. The next move is very often sitting in one of those three.
3. Finish nearly-full regions. A box with one gap costs you nothing to complete, and completing it usually unlocks its neighbours.

Three things worth doing from the very first game

• Never guess. Every SudokuStreak puzzle has exactly one solution reachable by pure logic, so a guess is never necessary - and a wrong one poisons everything you deduce afterwards. Being stuck means there is a move you have not spotted, not that the puzzle needs luck.
• Do not reach for pencil marks yet. On Easy you rarely need them, and filling a grid with candidate digits before you need them slows you down. From Medium upward they become essential - that is what pencil marks are for.
• Let yourself make the mistake. Writing a digit that breaks a row is how the rule stops being abstract. The board marks it, you fix it, and it costs you nothing but a moment.

What to play next

Start with an Easy 9×9 - it is built so the moves above are always enough. If a full grid still feels like a lot to hold in your head, the Mini 4×4 and Mini 6×6 boards use the identical rules on fewer squares, which makes the reasoning easier to see.

When Easy stops taking any thought, read the twelve beginner habits for how to practise deliberately, then which technique each difficulty actually needs before you move up.