Daijō-daijin in the context of "Dajōkan"

Shogun (将軍, shōgun; English: /ˈʃoʊ.ɡʌn/ SHOH-gun, Japanese: [ɕoː.ɡɯɴ, -ŋɯɴ] ), officially seii taishōgun (征夷大将軍; Japanese: [seꜜi.i | tai.ɕo(ꜜ)ː.ɡɯɴ, seꜜː-, -ŋɯɴ] lit. 'Commander-in-Chief of the Expeditionary Force Against the Barbarians'), was the title of the military rulers of Japan during most of the period spanning from 1185 to 1868. Nominally appointed by the Emperor, shoguns were usually the de facto rulers of the country, except during parts of the Kamakura period and Sengoku period when the shoguns themselves were figureheads, with real power in the hands of the shikken (執権) of the Hōjō clan and kanrei (管領) of the Hosokawa clan. In addition, Taira no Kiyomori and Toyotomi Hideyoshi were leaders of the warrior class who did not hold the position of shogun, the highest office of the warrior class, yet gained the positions of daijō-daijin (太政大臣, Chancellor of the Realm) and kampaku (関白, Imperial Regent), the highest offices of the aristocratic class. As such, they ran their governments as its de facto rulers.

The office of shogun was in practice hereditary, although over the course of the history of Japan several different clans held the position. The title was originally held by military commanders during the Heian period in the eighth and ninth centuries. When Minamoto no Yoritomo gained political ascendency over Japan in 1185, the title was revived to regularize his position, making him the first shogun in the usually understood sense.

Toyotomi Hideyoshi (豊臣 秀吉; Japanese pronunciation: [to.jo.to.mʲi (|) çi.de(ꜜ).jo.ɕi], 27 March 1537 – 18 September 1598), otherwise known as Kinoshita Tōkichirō (木下 藤吉郎) and Hashiba Hideyoshi (羽柴 秀吉), was a Japanese samurai and daimyō (feudal lord) of the late Sengoku and Azuchi-Momoyama periods and regarded as the second "Great Unifier" of Japan. Although he came from a peasant background, his immense power earned him the rank and title of Kampaku (関白, Imperial Regent) and Daijō-daijin (太政大臣, Chancellor of the Realm), the highest official position and title in the nobility class. He was the first person in history to become a Kampaku who was not born a noble. He then passed the position and title of Kampaku to his nephew, Toyotomi Hidetsugu. He remained in power as Taikō (太閤), the title of retired Kampaku, until his death. It is believed, but not certain, that the reason he refused or could not obtain the title of shogun (征夷大将軍), the leader of the warrior class, was because he was of peasant origin.

Hideyoshi rose from a peasant background as a retainer of the prominent lord Oda Nobunaga to become one of the most powerful men in Japanese history. He distinguished himself in many of Nobunaga's campaigns. After Nobunaga's death in the Honnō-ji Incident in 1582, Hideyoshi defeated his assassin Akechi Mitsuhide at the Battle of Yamazaki and became Nobunaga's successor. He then continued the campaign to unite Japan that led to the closing of the Sengoku period. Hideyoshi became the de facto leader of Japan and acquired the prestigious positions of daijō-daijin and kampaku by the mid-1580s. He conquered Shikoku in 1585 and Kyūshū in 1587, and completed the unification by winning the Siege of Odawara in 1590 and crushing the Kunohe rebellion in 1591. With the unification of Japan complete, Hideyoshi launched the Japanese invasions of Korea in 1592 to initial success, but eventual military stalemate damaged his prestige before his death in 1598. Hideyoshi's young son and successor Toyotomi Hideyori was displaced by Tokugawa Ieyasu at the Battle of Sekigahara in 1600 which would lead to the founding of the Tokugawa Shogunate.

Minister of the Right (右大臣, Udaijin) was a government position in Japan during the Asuka to Meiji era. The position was consolidated in the Taihō Code of 701. The Asuka Kiyomihara Code of 689 marks the initial appearance of the Udaijin in the context of a central administrative body called the Daijō-kan (Council of State). This early Daijō-kan was composed of the three ministers—the Daijō-daijin (Chancellor), the Sadaijin (Minister of the Left) and the Udaijin. The Udaijin was the Junior Minister of State, overseeing all branches of the Daijō-kan. He would be the deputy of the Sadaijin.

From the Kamakura period (1185–1333), when the warrior class came to power in Japan, this imperial court position became an honorary position with no real authority. Oda Nobunaga, who was a powerful daimyo in the Azuchi-Momoyama period, was a daimyo who held this imperial court position. This was the first time since Minamoto no Sanetomo in 1218 that a member of the warrior class had been appointed Udaijin. Previously, the only warrior class members appointed to higher positions than Udaijin were Taira no Kiyomori and Ashikaga Yoshimitsu as Daijō-daijin, and Ashikaga Yoshinori and Ashikaga Yoshimasa as Sadaijin. The warrior class was able to use the high imperial court positions of Daijō-daijin, Sadaijin, and Udaijin, which had originally belonged to the nobility, as a means of establishing their own authority.

The Minister of the Left (左大臣, Sadaijin) was a government position in Japan during the Asuka to Meiji era. The Asuka Kiyomihara Code of 689 marks the initial appearance of the Sadaijin in the context of a central administrative body called the Daijō-kan (太政官, Council of State). This early Daijō-kan was composed of the three ministers—the Daijō-daijin (太政大臣, Chancellor of the Realm), the Sadaijin and the Udaijin (右大臣, Minister of the Right). The position was consolidated in the Taihō Code of 702.　In Yamto kotoba（ヤマト言葉）, it is also called "Ohoi-Mauchi-Kimi"於保伊萬宇智岐美.

When the Emperor and the nobility held real power, the Sadaijin was the highest permanent position in the Daijō-kan, the central organ of the state. The higher-ranking 'Daijō-daijin was not a permanent position, but was only appointed when a suitable person was found.The Sadaijin was the Senior Minister of State, overseeing all functions of government with the Udaijin as his deputy.