In fact, what Li Hongzhang signed was not the word "su", but a monogram that resembled the word "su". This monogram was actually more formal than his signature. Monograms originated in the Tang Dynasty and became popular during the Song Dynasty. It is somewhat similar to today's seals, but it is written. In ancient times, many literati used monograms instead of signatures as their own symbols. Most of the tribute documents from the Song Taizu and Taizong periods only had monograms but no signatures. Literati usually incorporated their names when designing monograms, but they did not simply present their names directly.

For example, what Li Hongzhang signed on the "Xin Chou Treaty" was actually a monogram that incorporated the strokes of his own name. This monogram tightly stacks the three characters "Li Hongzhang" together according to writing habits, making it look like the character "solemn". In addition to Li Hongzhang, Prince Qing, who signed the "Xinchou Treaty" with him on behalf of the Qing government at the time, also used a monogram instead of a signature. The reason why this kind of monogram can be used in formal documents is that everyone's monogram is designed by himself. Only the designer himself knows the writing order and many details, so it is more difficult to imitate than a signature.

People who mistakenly think that this monogram is the word "su" usually guess that Li Hongzhang used the word "su" instead of his signature because he did not want to leave his name on this treaty that was humiliating and humiliating the country. Of course, some people think that Li Hongzhang was the "first-class uncle Su Yi", so he used "Su Yi" to sign the "Xinchou Treaty". In fact, this is not the case. Except for the "Xinchou Treaty", Li Hongzhang still signed this monogram that looks like the word "su" in other treaties.

Li Hongzhang was not actually a treacherous minister who was only interested in profit, but because he signed unequal treaties on behalf of the Qing government many times, he suffered a lot of infamy for no reason. In that turbulent era, no matter how hard Li Hongzhang tried to change the social ills, it was to no avail. Even though he argued hard before signing the unequal treaty, he had to sign the treaty as a representative again and again.