What is the calligraphy attainments of Ou Yangxun, a calligrapher in Sui and Tang Dynasties?

Ou Yangxun (557 ~ 64 1) was born in Linxiang, Tanzhou (now Changsha, Hunan). The Sui Dynasty was a doctor in Taichang, and the Tang Dynasty was a bachelor's prince in Hong Wen Pavilion. Feng Nan is from Bohai County. He was a famous calligrapher in the early Tang Dynasty, ranking first among the four calligraphers, and was also called "Ou Yu" with Yu Shinan. The Book of the Tang Dynasty said that he "imitated Wang Xizhi's book at first, and later passed it on because of his own name." According to these letters, people think this is the law. "He is good at talking about structure and has handed down papers such as the Thirty-six Laws. His font structure is very precise and rigorous, and he is known as "precipitous". Later generations began to learn books from He Lin's words. His masterpiece is "The Ritual Spring Inscription of Jiucheng Palace". Engraved in the sixth year of Zhenguan (632). There are also Huadu Temple Monument and Huangfushengchen Monument. The ink handed down from ancient times includes Meng Diantie, Tie and Hans Zhang Tie.