Strength in numbers

The burgeoning popularity of Sudoku in China is not only improving youngsters' logical thinking, but fueling success at international competitions, Xing Wen reports.

It's Friday, and 500 primary school and junior high school students sit in a hall in Xianghe county, North China's Hebei province, each using a pencil to fill in the empty squares of a grid that is divided into nine blocks of nine squares each.

These young finalists have been selected from the preliminary contests of this year's national junior Sudoku competition which were held in Beijing, Shanghai, Hangzhou and 15 other cities across the country. Some of them are hoping to gain entry into the 2018 China Sudoku Championship on Saturday, where they will fight for the opportunity to represent the country at this year's World Sudoku Championship in Prague, the capital of the Czech Republic.