This font is called "Pavilion Style", which is a kind of regular script font.
Pavilion first appeared in the Ming Dynasty, and the famous representative was Shen Du, a calligrapher in the Ming Dynasty.
Pavilion style refers to the writing style popular in pavilions and imperial examination rooms, belonging to official script style, especially regular script, which is square, smooth, black and even. It was called "Taige Style" in Ming Dynasty and renamed "Pavilion Style" in Qing Dynasty.
As can be seen from the picture, this is a work of Jiaqing period in Qing dynasty, which was already called "pavilion style" at that time.
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