A concrete order of operations for the opening of a Sudoku board — sweep, cross-hatch, then count — that removes most of the guessing from level one.
Almost every slow Sudoku player is slow for the same reason: they read the board in a random order. They find a five, then lose it, then find it again twenty seconds later. Scanning is the fix, and it is a fixed sequence you can run on autopilot.
This is the exact order we recommend for the first ninety seconds of any PlayJoy Sudoku board.
Pass one — sweep the completed rows
Start with the rows, boxes or columns that already hold the most given digits. Each of those constrains its neighbours hardest, so they give up their answers first.
Work one digit at a time rather than one cell at a time. Pick the digit that appears most often among the givens and sweep the whole grid for it before moving to the next digit.
Pass two — cross-hatch the boxes
For a single digit, take two of its instances and draw the rows and columns they eliminate through a target box. If eight of the nine cells are ruled out, the ninth is your answer.
Cross-hatching is mechanical and it is where most of the "free" cells on an easy board live. Do not skip it because it feels slow — it is faster than guessing and undoing.
Pass three — count, do not guess
When a sweep stalls, pick the most constrained cell — the one with the fewest candidates — and count what is missing in its row, column and box. Three intersecting constraints usually reduce the cell to a single digit.
Only after three full passes should you consider a deeper technique. On the daily board, level one and most of level two yield to scanning alone.
Why order beats speed
Random scanning re-reads the same cells and re-derives the same eliminations, which is where the minutes go. A fixed order touches each cell once per pass.
Our scoring multiplies difficulty by a time constant, so shaving thirty seconds off level one is worth roughly the same as a correct hard cell on level three — and it is much more reliable.
FAQ
Should I fill in pencil marks while scanning?
Not during the first pass. Pencil marks slow down the sweep and are better used once the board stalls — see our note on pencil mark discipline.
What if two passes find nothing?
Switch to counting on the most constrained cells. If a whole digit sweep produces nothing three times in a row, you have likely mis-copied an elimination.