A drought-resistant, fast-ripening rice strain acquired by China from Vietnam (Champa) during the Song Dynasty. This variety matured more quickly than traditional rice, allowing for two harvests per year in many regions.
Its adoption significantly impacted demographics and agriculture. The increased food supply supported a larger population and fueled urbanization. Land that was previously unsuitable for rice cultivation became productive, leading to agricultural expansion and economic growth. It also contributed to shifts in social structures and labor practices as farmers adapted to the new crop.