While most people play sudoku by themselves, these codes are decidedly communal. Scott Armstrong, a solver in Philadelphia, said that applying the more complex strategies gave him new ways to ...

But when it comes to boosting brain power, which one is better? Sudoku is a logic-based number puzzle played on a 9x9 grid.

Everyone can try a few sudoku puzzles for free, but Apple News Plus subscribers can play new puzzles every day. An Apple News Plus subscription is $13 a month and gives you access to daily Sudoku ...

New to the game or need a refresher of the rules? Sudoku is played on a grid of nine-by-nine spaces, and within the rows and columns are nine squares, each made up of three-by-three spaces.