Sudoku Online: Free Online Sudoku Games 87

Sudoku offers free online Sudoku games. Sudoku is a popular logic puzzle game where the goal is to fill a 9x9 grid so that each row, each column, and each 3x3 sub-grid contains all the numbers from 1 to 9. Playing this game requires no calculations or special math skills, only wit and concentration. Playing it every day can also boost your attention and overall intelligence. Users can start the game right away.

Features of Sudoku Online Game

• Completely free, play instantly: Open the webpage and play Sudoku right away, no registration required.

• Standard rules: Fill the 9×9 grid, ensuring that the numbers 1 - 9 do not repeat in each row, each column, or each 3×3 box.

• Four difficulty levels: There are four difficulty levels - Easy, Medium, Hard, and Expert - and you can switch between them at any time.

• Daily new puzzles: A "Daily Challenge" puzzle is updated every day, allowing you to check in and rack up points.

• Beginner tips: Two built-in quick-start tips help new players get up to speed quickly.

• Multi-device sync: iOS/Android apps are available, game progress syncs in the cloud, and offline play is supported.

How to Play Sudoku?

• Enter the game: Open sudoku.com/zh, and the page will automatically load a 9×9 Sudoku board, with some cells already pre-filled with numbers.

• Select difficulty: Click the difficulty buttons at the top (Easy / Medium / Hard / Expert), and the system will regenerate a puzzle of the corresponding difficulty. Beginners are advised to start with the "Easy" level.

• Fill in numbers: Click on an empty cell with the mouse, and that cell will be highlighted. Then click a number on the number pad (1 - 9) at the bottom to fill it into the cell. If you fill in the wrong number, you can click the number pad again or press the Delete/Backspace key to erase it.

• Use the helper features (optional)

• Draft mode: Click the "Notes" toggle to write small numbers in a cell as candidate numbers.

• Highlighting: After entering a number, all identical numbers will be highlighted for easy checking.

• Hints: Click the "Lightbulb" button, and the system will help you fill in a correct cell, but it may add time or deduct points.

• Verification and completion: When all 81 cells are filled and the rules are satisfied, the page will pop up a "Congratulations on completing" message and show the time taken. If a duplicate number appears in any row, column, or box, the conflicting area will turn red as a reminder, and you need to fix it promptly.

Sudoku Tips

• Find rows, columns, or 3×3 boxes where 5 or more numbers have already appeared: In these areas, the remaining empty cells can quickly narrow down to a single candidate number.

• Find identical numbers from "big rows and columns": View the board as 3 big columns (each containing three 3x3 sub-grids) and 3 big rows (each containing three 3x3 sub-grids). If two 3×3 boxes already contain the same number, then the third box must contain that same number in the same row or column, which helps eliminate some positions.

Incorrect Filling Determination

A Sudoku filling is incorrect if any of the following occurs: more than one identical number from 1 to 9 appears in any row; more than one identical number from 1 to 9 appears in any column; more than one identical number from 1 to 9 appears in any 3x3 sub-grid.

Beginner Tips for Sudoku

For complete beginners with no Sudoku experience, the website offers two practical tips:

• Tip 1: Focus on highly filled sub-grids

• Steps: Find a 3x3 sub-grid whose row and column already contain 5 or more numbers.

• Filling logic: Try using the numbers not yet used within that sub-grid (i.e., the missing numbers from 1 - 9) to fill the remaining empty cells. In most cases, combined with the existing numbers in other rows, columns, and 3x3 sub-grids, you'll find that there is only one place to fill a number in the remaining empty cells.

• Tip 2: Find identical numbers from "big rows and columns"

• Grid division: View the entire 9x9 grid as 3 big columns (each containing three 3x3 sub-grids) and 3 big rows (each containing three 3x3 sub-grids).

• Operating logic: Find 2 columns or 2 boxes that share the same number. By logic, you can infer that among the remaining 9 cells, there must be a third identical number. Checking these 9 positions one by one will help you determine the correct position of this missing number.

Play a game of Sudoku every day, and with consistent practice you'll get faster and faster. Playing Sudoku at sudoku.com/zh provides both entertainment and a boost to attention and overall intelligence. This Sudoku game from Sudoku is completely free, and users can start playing immediately. Sudoku is a popular logic puzzle game with easy-to-understand rules that require no special skills. Beginners can quickly get started with the tips provided by the platform, making it easy to become a favorite free online game for users.