Sudoku for Beginners: A Simple Method That Solves Easy Puzzles
The rules, two basic techniques and a step-by-step routine that solves most easy and medium sudoku.
Sudoku needs no math at all. It is a logic puzzle with digits as symbols, and two simple techniques solve most easy and medium puzzles.
The rules
Fill the 9x9 grid so that every row, every column and every 3x3 box contains the digits 1 to 9 exactly once. A well-made puzzle has only one solution, so you never need to guess.
Technique 1: the only place
Pick a digit, say 5, and a 3x3 box that doesn't have a 5 yet. Look at the rows and columns that already contain a 5; they block squares in your box. If only one empty square is left for 5 in that box, the 5 goes there. Do the same for rows and columns.
Technique 2: the only candidate
Pick an empty square. Check its row, its column and its box and list which digits are still possible. If only one digit is possible, write it in.
A routine that works
- Start with the digit that already appears most often in the grid.
- Scan every box for "the only place" for that digit, then move to the next digit.
- When scanning stops giving answers, switch to "the only candidate" in the fullest rows and boxes.
- Every new digit opens new options, so go back to scanning.
Use pencil marks
In harder puzzles write the possible digits small in the corners of a square. When a candidate is ruled out, cross it off. This keeps you from holding everything in your head.
Large print helps
Big clear digits and generous squares make pencil marks readable and reduce mistakes. Our Large Print Sudoku has 100 puzzles from easy to expert, one per page, each with exactly one solution checked by computer, and answers at the back.
Large Print Sudoku: 100 Puzzles
100 large-print sudoku puzzles from easy to expert, one per page, answers included. US Letter + A4 PDF, 119 pages.