These four characters was written by Yan Zhenqing, a famous calligrapher in the Tang Dynasty (618?907) who had created the Yan-style calligraphy. Characters in this style with the shape like silkworm head and swallow tail need high accomplishments in calligraphy. The character “?(means sword)” was actually written by Yan and “?(means pool)” is fake according to research. So it has the name of “Real sword and fake pool”. And the name also has another meaning, implying the secret of He Lv Tomb, because the east and west cliff of the Sword Pool is shaped by nature, and the behind hill of Huqiu is formed manually in order to cover up the entrance of the tomb.