Yamato Kingship in the context of Taika Reform

Yamato Province (大和国, Yamato no Kuni; Japanese pronunciation: [jaꜜ.ma.to (no kɯ.ɲi)]) was a province of Japan, located in Kinai, corresponding to present-day Nara Prefecture in Honshū. It was also called Washū (和州). Yamato consists of two characters, 大 "great", and 和 "Wa". At first, the name was written with one different character (大倭), but due to its offensive connotation, for about ten years after 737, this was revised to use more desirable characters (大養徳) (see Names of Japan). The final revision was made in the second year of the Tenpyō-hōji era (c. 758). It is classified as a great province in the Engishiki.

The Yamato Period in the history of Japan refers to the late Kofun Period (c. 250–538) and Asuka Period (538–710). Japanese archaeologists and historians emphasize the fact that during the early Kofun Period the Yamato Kingship was in close contention with other regional powers, such as Kibi Province near present-day Okayama Prefecture. Around the 6th century, the local chieftainship gained national control and established the Imperial court in Yamato Province.

The recorded military history of Japan began in 2nd century during the Yayoi period.

The Yamato tribal alliance fought amongst the Three Kingdoms of Korea, in the 5th century against Goguryeo and Silla and in 663 against Silla and Tang dynasty forces.

The Yamato period (大和時代, Yamato-jidai) is the period of Japanese history when the imperial court ruled from modern-day Nara Prefecture, then known as Yamato Province.

While conventionally assigned to the period 250–710, including both the Kofun period (c. 250–538) and the Asuka period (538–710), the actual start of Yamato rule is disputed. The Yamato court's supremacy was challenged during the Kofun period by other polities centered in various parts of Japan. What is certain is that Yamato clans had major advantages over their neighbouring clans in the 6th century. This period is divided by the relocation of the capital to Asuka, in modern Nara Prefecture. However, the Kofun period is an archaeological period while the Asuka period is a historical period. Therefore, many think of this as an old division and this concept of period division is no longer applicable.

The Silla–Goguryeo and Paekche–Kaya–Wa War (Korean: 나여–제야왜 전쟁; Hanja: 羅麗・濟倻倭 戰爭; RR: Nayeo–Jeyawae Jeonjaeng; MR: Nayŏ–Cheyawae Chŏnjaëng) was a series of conflicts that spanned for 40 years from the mid 4th century to the early 5th century between the Silla–Goguryeo alliance and the Paekche–Kaya–Wa alliance according to the Samguk sagi, Samguk yusa, Nihon Shoki, and inscriptions found in the Gwanggaeto Stele.

It was the first and only time where all four nations of Korea (Goguryeo–Silla–Paekche–Kaya) were involved in a single war, and Wa (Japan)'s first international conflict prior to the introduction of the Yamato Kingship and the following Battle of Baekgang that came after.

The Battle of Baekgang (Korean: 백강 전투; Hanja: 白江戰鬪) or Battle of Baekgang-gu, also known as the Battle of Hakusukinoe (Japanese: 白村江の戦い, romanized: Hakusuki-no-e no Tatakai / Hakusonkō no Tatakai) in Japan, and as the Battle of Baijiangkou (Chinese: 白江口之战; Chinese: 白江口之戰; pinyin: Bāijiāngkǒu Zhīzhàn) in China, was a battle between Paekche restoration forces and their ally, Yamato Japan, against the allied forces of Silla and Tang China. The battle took place on 27–28 August 663 (of the Lunar calendar; 4–5 October 663 of the Julian calendar) in the Baengma River (Korean: 백마강; Hanja: 白馬江) or Baek River (Korean: 백강; Hanja: 白江), which is the lower reach of the Geum River in Jeollabuk-do province, Korea. The Silla-Tang forces won a decisive victory, compelling Yamato Japan to withdraw completely from Korean affairs and crushing the Paekche restoration movement.