The best regular script in the world refers to Yan Zhenqing's Magu Mountain Xiantan. In the sixth year of the Tang Dynasty, Yan Zhenqing, a great calligrapher, visited Magu Mountain and wrote the Fairy Altar of Magu Mountain, the full name of which is Magu Mountain Fairy Altar in Nancheng County, Fuzhou in the Tang Dynasty. This is a monument in the history of China's calligraphy, a masterpiece of Yan Zhenqing's calligraphy, and is praised as "the best regular script in the world" by later generations.