Sudoku

In the eighty-one lattices, given some known numbers and solution conditions, using logic and reasoning, fill in the other blanks with 1-9 numbers. Make 1- 9 each number appear only once in every row, column and palace, so it is also called "Nine Palaces".
1. There are four kinds of difficulty, easy, medium, hard, expert.
2. Statistics, track progress at each difficulty level: analyze your best time and achievements
3. There are also tips and note-taking functions, often play more fun, more use of the brain will not be old.

The Sudoku board is composed of nine palaces, and each palace is divided into nine small grids. Give certain known numbers and problem-solving conditions in these eighty-one grids, and use logic and reasoning to fill in the numbers 1-9 in the other blanks. Make each number 1-9 appear only once in each row, column and house, so it is also called "Nine Palaces".
1. Contains four levels of difficulty, easy, medium, hard, expert
2. Statistics, track your progress for each difficulty level: analyze your best times and achievements
3. There are also reminder and note functions. It is a lot of fun to play often, and you will not get old if you use your brain more.