Start with the three rules
A standard Sudoku puzzle is built around one idea: every row, every column, and every 3x3 box must contain the numbers 1 to 9 once. You do not add numbers or use arithmetic. The numbers are labels for a logic puzzle.
Before placing a number, check those three areas. If the same number already appears in the row, column, or box, that move is not allowed.
Look for the most complete areas first
New players often scan the whole grid at random. A better habit is to start with a row, column, or box that already has many numbers. Fewer blanks means fewer candidates to test.
This makes the first move less mysterious. You are not trying to solve the whole puzzle at once; you are looking for one cell where logic leaves only one possible answer.
- Scan boxes with six or more given numbers.
- List the missing numbers from 1 to 9.
- Check each missing number against the crossing rows and columns.
- Place a number only when every other option is blocked.
Use notes before guessing
If two or three numbers could fit in a cell, write them as notes and keep moving. Guessing can make a puzzle look solved for several moves before a contradiction appears.
Notes turn uncertainty into visible information. As nearby cells get solved, notes become easier to remove.
Practice with a guided page
This article is a short learning entry. The full guide includes a 9x9 example board and a step-by-step first move walkthrough.