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Your First Sudoku: A Walkthrough of the First Five Minutes
A fresh puzzle can look like a wall of empty squares. Here is exactly what an experienced solver does in the first five minutes, so you can do the same.
Minute 1: Look before you write
Take a few seconds to look at the whole grid. Which numbers appear most often? Which boxes are crowded? You are not solving yet, just getting a feel for the puzzle.
Minute 2: Start with the most common number
Pick the number that appears most often. Go box by box and use scanning to see where it can go. With so many copies already placed, you will often find one or two new spots right away.
Minute 3: Follow every success
Each time you write a number, look at its row, column and box. Did it leave a row with only one empty cell? Did it finish a pattern for another number? Follow the chain as far as it goes.
Minute 4: Go through all the numbers
Work through 1 to 9 in order. Some numbers will give you nothing. That is normal. Keep moving; the grid is changing as you fill it.
Minute 5: Find the crowded rows
Look for any row, column or box with only two or three empty cells. Ask which numbers are missing and where each could go. These nearly finished areas often solve themselves.
Keep calm and keep looking
Every solver gets stuck. The difference is that experienced solvers expect it. When a move does not appear, they change direction: from boxes to rows, from rows to columns, from one number to the next. The answer is always there, waiting to be noticed.