Sudoku is not a new game,but recently I begin to play it frequently with no reason.Perhaps I want to get a higher IQ. 

With a reference of Wiki,Sudoku,in short,is a logic-based number-placement puzzle.The objective is to fill a 9×9 grid so that each column, each row, and each of the nine 3×3 boxes (also called blocks or regions) contains the digits from 1 to 9 only one time each. The puzzle setter provides a partially completed grid.

I always visit WebSudoku playing online.In that website,you could choose your preferred difficulty levels of games to fit your demands-a challenge or only a relaxation.

During the long holidays,if you feel bored,just go to play it.It will definitely help to remove your depressed mood and probably let you be smarter with no cost.Isn’t it perfect?