戰國時代各國競相追求變法圖強之道，秦孝公重用商鞅進行變法，確立秦國以「農」富國，以「戰」強兵的基礎，商鞅變法改革是秦國由弱轉強的關鍵。至秦惠文王即位，對內繼續貫徹重農的經濟政策，積極地以農業發展關中地區，以及新取得的巴蜀、漢中等地；對外則在兼併戰爭中達到開疆拓土的目的。自秦國確立農業為經濟發展的基本國策，秦國的繼任者繼續取得戰爭的勝利，並將推行農業的手段帶到新兼併地，因而有效地鞏固新兼併地，約一百餘年的時間而有秦王政併吞六國，此乃魏武所言「秦人以急農兼天下」之由。

All States sought the way to be prominent by reforming in Warring States period. Duke Xiao of Qin employed Shang Yang to enact numerous reforms which helped Qin to have great foundation to unify states by agriculture and military power. This reform was the turning point for Qin to be powerful and strongly centralized kingdom. After King Qin Huiwen ruled the state of Qin, he kept executing this reform which focused on agriculture to develop the Guanzhong Plain and then got the territory of Basu and Hanzhong. He also outreached the territory of Qin by annexing others'. Since Qin established its fundamental state tactic, developing agriculture, the following successors had kept having victories on wars and bringing the tactic to the new lands. Furthermore, they, the following successors, had been controlling and reinforcing the new lands efficiently for about 100 years. Afterwards, King Zheng of Qin unified six states into a state. Wei Wu described that "Qin annexed, unified and ruled the states by agriculture".