Do you know？
Sudoku is a relatively new game. It started in 1970s in America. In 1980s a Japanese magazine officially named this game 'Sudoku'. It means that there is only one number in each grid. Ever since then, it's getting more and more popular in Japan. Around 2005, it became a worldwide common game, due to the popularity of the Internet.
Sudoku game board contains 81 grids in 9 blocks, made up of 9 rows and 9 columns. The purpose is to put 9 numbers in blank grids and make sure that all 9 numbers in each row, each column and each block are all different.
How to play:
1. Choose a grid.
2. Select one number based on the game rules.
Here are the tips to help you locate answers much quicker:
1. Highlight: when you choose any number on the board, all the same number that has been filled in will be highlighted! Now it becomes easier, right? If you don't want this, you can simply turn it off on the settings page.
2. Hint: When you get stuck, choose a grid and tap on the light bulb in the upper right corner. You will find the answer of that grid will just popup by itself! Please notice: the number of used hint will affect your final score!
Three clears in one level will bring you to the higher difficulty level!