This post is one of the volumes of Song Sijia's Essays collected by the National Palace Museum. This is a letter, named after the word "crossing the sea" in it. And because there is a "poem" at the end of the volume. Dream secret school, your Excellency. The words "June 13th" are also called "The Secret School Letter to Dream" or "The Secret School Book to Dream". This work was collected by Xiang Yuanbian in the Ming Dynasty, copied by Chen Jiru into "Late Fragrant Hall Sutie", returned to Da Zhongguang in the early Qing Dynasty, and later entered the Qing Dynasty Palace in Tibet, and recorded in "The Sequel of Shiqu Baodi". Judging from its collection process, it can be said that there are many stories circulating. This volume has no inscriptions of collectors in past dynasties. It was only in recent years that he died in the world. In the 193s, it was included in The Complete Works of China's Calligraphy and Taoism, and later it was selected by the National Palace Museum. In recent years, it has been included in the Collection of Paintings and Calligraphy in the National Palace Museum in Taipei and the Dictionary of China Calligraphy Appreciation edited by Liu Zhengcheng. In addition, Xue Cun Uno's History of Calligraphy and Taoism in China and some calligraphy history published by China in recent years are also regarded as authentic works of Su Shu, so they are reviewed. When commenting on this work, the above-mentioned scholars have different aesthetic angles, but they are all praised as Su Shu's masterpiece. Now, the entries of Crossing the Sea in China Dictionary of Calligraphy Appreciation are selected for your reference. This entry says: "Su Shi wrote on June 13th, Yuan Fu San (11). Paper book. Running script Collected by the National Palace Museum in Taipei. Published in Japan's Complete Works of Calligraphy and Taoism (XV). The "appreciation" of this article goes: "Dongpo has a lot of ink handed down from generation to generation, but the secret school letters that lead to dreams seem to be little known. However, the artistic value of this post is not under other ink, which is one of Dongpo's representative works. " "As a general correspondence, it is often unintentional, but the more casual, the more you can observe people's temperament. The whole essay is less than 1 words. It's magnificent and written, but it's full of interest. It's really like what he himself said,' I didn't mean to Yoga Yu at the beginning of the book, but it was a good ear.'' Although my book is not very good, it is a quick one if I don't practice the ancients.' Dongpo's book does not fall into the stereotype of the ancients. Here, we can't see any lingering charm of Wei and Jin Dynasties and the pedantic attitude of the Tang Dynasty, but some are just naive and innocent feelings. The whole composition is uneven, the length is appropriate, the font size is scattered, and it is natural, the ink color is dripping, and it is thick and plump. In particular, the more words are written behind, the more indulgent they are, and they forget the rules. Between the pen and ink, there is a melancholy Sandy, which is beyond the dust and vulgar, and is still a fairy in the book. ".