In the Ming Dynasty Jiao Hu's "Miscellaneous Books and Mistakes", the anchor "is the device that is now placed in the shape of a quadrangular fork placed on the bow and stern of the ship. It can be worn with iron ropes, and can be fixed in the water to prevent the ship from moving." Because the anchor has iron claws extending in four directions, it can be plunged into the mud to grab the soil, just like the cat's claw, so in ancient books, "anchor" is written "緢", or simply written " "Cat" word. Such as writing cats in Zhou Mi's "Sequels of Guixin Miscellaneous Knowledge · Hai maggots" in Yuan Dynasty. In the Qing Dynasty, He Changling (Jiangsu Maritime Case), when referring to materials related to Song Yingxing (Tiangong Kaiwu), also changed the "anchor" to "cat". General sea ships, especially sea ships, have large anchors