Samurai () were the hereditary military nobility and officer caste of medieval and early-modern Japan from the late 12th century until their abolition in 1876. They were the well-paid retainers of the daimyo (the great feudal landholders). They had high prestige and special privileges such as wearing two swords and Kiri-sute gomen (right to kill anyone of a lower class in certain situations). They cultivated the bushido codes of martial virtues, indifference to pain, and unflinching loyalty, engaging in many local battles.

Though they had predecessors in earlier military and administrative officers, the samurai truly emerged during the Kamakura shogunate, ruling from c.1185 to 1333. They became the ruling political class, with significant power but also significant responsibility. During the 13th century, the samurai proved themselves as adept warriors against the invading Mongols. During the peaceful Edo era (1603 to 1868), they became the stewards and chamberlains of the daimyo estates, gaining managerial experience and education.

In the 1870s, samurai families comprised 5% of the population. As modern militaries emerged in the 19th century, the samurai were rendered increasingly obsolete and very expensive to maintain compared to the average conscript soldier. The Meiji Restoration ended their feudal roles, and they moved into professional and entrepreneurial roles. Their memory and weaponry remain prominent in Japanese popular culture.

Duke Itō Hirobumi (伊藤 博文, 16 October 1841 – 26 October 1909, born as Hayashi Risuke and also known as Hirofumi, Hakubun and briefly during his youth as Itō Shunsuke) was a Japanese politician and statesman who served as the first Prime Minister of Japan. He was also a leading member of the genrō, a group of senior statesmen that dictated Japanese policy during the Meiji era.

A London-educated samurai of the Chōshū Domain and a central figure in the Meiji Restoration, Itō Hirobumi chaired the bureau which drafted the Constitution for the newly formed Empire of Japan. Looking to the West for inspiration, Itō rejected the United States Constitution as too liberal and the Spanish Restoration as too despotic. Instead, he drew on British and German models, particularly the Prussian Constitution of 1850. Dissatisfied with Christianity's pervasiveness in European legal precedent, he replaced such religious references with those rooted in the more traditionally Japanese concept of a kokutai or "national polity" which hence became the constitutional justification for imperial authority.

During the 1880s, Itō emerged as the most powerful figure in the Meiji government. By 1885, he became the first Prime Minister of Japan, a position he went on to hold four times (thereby making his tenure one of the longest in Japanese history). Even out of office as the nation's head of government, he continued to wield enormous influence over Japan's policies as a permanent imperial adviser, or genkun, and the President of the Emperor's Privy Council. A staunch monarchist, Itō favored a large, all-powerful bureaucracy which answered solely to the Emperor and opposed the formation of political parties. His third term as Prime Minister was ended in 1898 by the opposition's consolidation into the Kenseitō party, prompting him to found the Rikken Seiyūkai party to counter its rise. In 1901, he resigned his fourth and final ministry upon tiring of party politics.

On the world stage, Itō presided over an ambitious foreign policy. He strengthened diplomatic ties with the Western powers including Germany, the United States and especially the United Kingdom. In Asia, he oversaw the First Sino-Japanese War and negotiated the surrender of China's ruling Qing dynasty on terms aggressively favourable to Japan, including the annexation of Taiwan and the release of Korea from the Chinese Imperial tribute system. While expanding his country's claims in Asia, Itō sought to avoid conflict with the Russian Empire through the policy of Man-Kan kōkan – the proposed surrender of Manchuria to Russia's sphere of influence in exchange for recognition of Japanese hegemony in Korea. However, in a diplomatic visit to Saint Petersburg in November 1901, Itō found Russian authorities completely unreceptive to such terms. Consequently, Japan's incumbent Prime Minister, Katsura Tarō, elected to abandon the pursuit of Man-Kan kōkan, which resulted in an escalation of tensions culminating in the Russo-Japanese War.

After Japanese forces emerged victorious over Russia, the ensuing Japan–Korea Treaty of 1905 made Itō the first Japanese Resident-General of Korea. Despite initially supporting the sovereignty of the indigenous Joseon monarchy, he ultimately consented to the total annexation of Korea in response to pressure from the increasingly powerful Imperial Army. Shortly thereafter, he resigned as Resident-General in 1909 and assumed office once again as President of the Imperial Privy Council. Four months later, Itō was assassinated by Korean-independence activist and nationalist An Jung-geun in Manchuria. The annexation process was formalised by another treaty the following year after Ito's death. Through his daughter Ikuko, Itō was the father-in-law of politician, intellectual and author Suematsu Kenchō.