grindstone

　　The spacious platform is a place for annual ritual ceremonies, with a cauldron shaped incense burner, iron cast turtles and cranes, a Four Seas Auspicious Jar, and a bronze altar on the platform. The bronze sacrificial table is used to place tribute items during the annual ritual ceremony. The bottom of the table is made of stone, and the top is made of solid bronze casting. There is a finger wide slot on the table top. It is said that one year on the 13th day of the fifth lunar month, Lord Guan made a pilgrimage here to sharpen his knife. Water was needed to sharpen the knife, and it rained with good luck. When Lord Guan polished the knife and tested it, he lightly cut it, leaving a mark. Therefore, the people called this altar Lord Guan's sharpening stone, and on the 13th day of the fifth lunar month, it became Lord Guan's sharpening day.