Mahjong originated in Jiangsu, used to record the bird's barn caught reward. It has three symbols. Line, Circle, Character. The circle is mean the cross-section of the gun; the Line is for strung birds. The bonus is calculated based on the number of birds; 10,000 is the unit of rewards, and tens of thousands are the number of rewards eventually received. Mahjong is usually made of bamboo, bones or plastic, with small squares engraved with patterns or words. Mahjong has officially become a world intellectual sports project since April 2017.