Sudoku Standard

A plain 9x9 number grid sets the pace here. In Sudoku Standard, the board uses the classic Sudoku format with no hints and no added rule twists. Two difficulty choices change the number of prefilled digits. The easier option places more numbers on the grid, and the hard option leaves more blanks. Every puzzle has one valid answer.

How to play?

Place digits from the side block into the empty cells. Fill each row with 1 through 9 without repeating a number. Do the same for each column. Each 3x3 box also needs the full set from 1 to 9. Use the squares with the highest number of given digits first. Those clues guide the rest of the layout. A wrong number in one cell creates an error elsewhere on the board.