Sudoku Rules and Fair Play
Every Sudoku board follows the core logic rule that digits 1 through 9 must appear exactly once in each row, column, and 3x3 box. Ranked play adds extra fair-play conditions so leaderboard results stay comparable.
Core Sudoku rule
Each row, each column, and each 3x3 box must contain all digits from 1 to 9 with no duplicates.
Ranked timed rule set
Ranked play requires a signed-in timed run and excludes boards that use restricted actions such as reveal or other disqualifying behavior.
Penalty-based fairness
Some helper usage can remain available in ranked mode while still affecting eligibility or effective time when the rules say so.
Board and completion rules
A board is solved only when every editable cell is filled and the completed grid satisfies Sudoku constraints. Until then, the run remains active even if the timer is still moving.
Practice boards and daily boards may use the same puzzle logic while differing in how stats, streaks, and rankings are applied.
Leaderboard eligibility
Leaderboard placement depends on the current ranked rules shown in the app before a timed board starts. These rules can account for sign-in state, helper usage, penalties, reveals, and other fairness checks.
SudokuX may update ranked rules as needed to keep the leaderboard useful, reduce abuse, and make results easier to trust.
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