Japanese researchers discovered a large dakō iron sword and a giant bronze mirror in a 4th-century burial mound in the city of Nara. The two items were found last November in the Tomio Maruyama Tumulus. According to the local government groups, the 125-pound, shield-shaped decorated mirror was the first of its kind to be discovered, and the seven-foot iron serpentine dakō sword is the largest and oldest from the Kofun period (300 CE–710 CE) to be found. Experts say this allows the two items from the Tomio Maruyama Tumulus to be classified as national treasures. The shield-shaped mirror is two...