The "Book of Sui" (), finished in 636 CE, records changing the capital's name from "Yamadai" () to "Yamato" ():Wa is situated in the middle of the great ocean southeast of Baekje and Silla, three thousand "li" away by water and land. The people dwell on mountainous islands. …The capital is Yamato, known in the Wei history as Yamadai. The old records say that it is altogether twelve thousand "li" distant from the borders of Lelang and Daifang prefectures, and is situated east of Kuaiji and close to Dan'er. (81, tr. Tsunoda 1951:28)