Wujing Zongyao
During the Song Dynasty, one form of infantry dao was the "shoudao", a chopping weapon with a clip point. While some illustrations show them as straight, the 11th century Song military encyclopedia Wujing Zongyao depicts them with curved blades – possibly an influence from the steppe tribes of Central Asia, who would conquer parts of China during the Song period. Also dating from the Song are the falchion-like "dadao", the long, two-handed "zhanmadao", and the long-handled, similarly two-handed "buzhandao" (步战刀).