Tenka-toitsu (unification of the whole country) (天下統一)
Tenka-toitsu (or Tenga-toitsu) refers to the act of putting the whole country of Japan (except for most parts of Ryukyu and Ezo [inhabited area of Ainu]) under own control and unifying it, mainly during the period from the Seongoku Period (Period of Warring State) to the early Edo period. It is also called Tenka-itto.
The term 'Tenka' (the realm) refers to a concept in ancient China, which showed an area governed by an emperor, and was often used also in Japan. Shinkoku kan (view of divine land) which spread in and after the medieval period, then became a logic justifying the samurai government, and a person in paramount authority was called 'Tenkabito' (person becoming the ruler of the country).
In the Sengoku Period (Period of Warring States), Nobunaga ODA implemented a unification project by military power, under the slogan of 'Tenka-fubu' (a slogan that means that the samurai governs the whole world). When Nobunaga died in the Honnoji Incident, Hideyoshi TOYOTOMI, Oda family's vassal, succeeded to and accomplished the unification of the whole country which had been unaccomplished. The term 'Tenka' originally meant that the controlled territory was borderless. After unifying the whole of Japan in 1590, Hideyoshi started dispatching troops to Ming (the Bunroku-Keicho War) in 1592. The Hideyoshi's dispatch of troops to Korea ended in failure, and in the Edo period when the Tokugawa Shogun family ruled Japan, the term 'Tenka' was used in only referring to the Japanese archipelago.