Nara is located in the center of what is known today as the Kinai region of Japan. The ancient name for the region was the Go-Kinai ("five-within the royal domain"), referring to the five provinces of which it was composed: Settsu, Kawachi, Izumi, Yamato and Yamashiro. The name Yamato, presented above variously as a provincial unit (corresponding to the present-day Nara Prefecture), or geographical unit (the Nara Basin only), is also sometimes expanded and applied on a regional scale to mean the Kinai region. This is particularly true in scholarship dealing with the fifth and sixth centuries when Yamato was in ascendance. Therefore, the Nara Basin and its archeology are the keys to unlocking the mysteries of the emergence of Japanese civilization and the early state in Japan. These mysteries are entailed in the earliest recorded history of Japan—references to Japanese island "countries" and "queens" in the Chinese dynastic histories of the third to fifth centuries A.D., and references to "kings" and "emperors" in two late fifth- to early sixth-century sword inscriptions and in the extant chronicles of Japan compiled in the early eighth century.