Why did Zhao Mengfu only write four poems in "Eight Poems of Du Fu's Qiuxing"?

One day when I was reading posts, I accidentally saw Zhao Mengfu's cursive calligraphy work "Eight Poems of Du Fu's Qiuxing". Reading the signature, I found that there was a section that was re-titled forty years later. The two signatures are slightly different.

Looking at the entire poem, there are only four poems. Zhao Mengfu has already explained this in his signature: "The eight poems of Qiuxing in You Shaoling are the best songs of ancient and modern times. Jun Shen used this paper to ask for a book, because the paper was short and only four ears were available."

? "This poem was written by me forty years ago. People today may not think it is written by me. Zi'ang emphasized the title. It was the seventeenth day of the first month of the second year of Zhizhi." In the second year of Zhizhi, that is, 1322 AD, Zhao Mengfu was sixty-nine years old at this time and died in the same year.

This volume was written by Zhao Mengfu in his early years, probably around 1282 AD, when Zhao Mengfu was only about 29 years old. The writing of this book is delicate and the structure is neat and beautiful. It can be seen that many methods were borrowed from Orchid Pavilion.

? Now look at the main title of this volume, which is vivid, smooth and accessible. In his later years, Zhao Mengfu became more mature in calligraphy style. It can be said that both people and calligraphers are old.

? One day after Bingshen Xiaoxue, Huizhai wrote it in Wanyi.