Introduction: At the beginning of the Meiji period, circumstances combined to make the need for language reform vital. The development of national systems of education and communication, together with the increased freedom of movement within the country and the publication of newspapers and magazines, showed up vividly the deficiencies of written Japanese. Chapter One: There was a wide variety of styles in use among the upper classes, all of which were specialized and difficult. A high degree of education was needed to read and write them. They fell into four main categories - kanbun, sōrōbun, wabun and wakankonkōbun. These styles continued well into the Meiji period, some even later. Chapter Two: The first phase of the Genbunitchi movement was utilitarian in nature. Beginning with certain religious, instructive and popular literature in the Tokugawa period, men realized that the colloquial style had advantages in composition aimed at the common people. Several of the early enlightenment writers used it in their works. The Education Ministry attempted to put it into use around 1873, but was defeated. Other fields in which it appeared during the period before 1887 were popular newspapers, shorthand transcriptions, and political koshinbun of the civil rights movement. There was a certain amount of theorizing about it among intellectuals, which increased in volume after 1884. Chapter Three: With the appearance of Genbunitchi in literature in 1887, the movement assumed a new importance. Several young writers followed the lead of Futabatei Shimei and Yamada Bimyō in adopting colloquial style. Genbunitchi suffered a setback for a few years in the early 1890's, as the result of a return to the traditional styles during a wave of nationalistic feeling, but reasserted itself after 1895 when Ozaki Kōyō made it into a highly-polished style, superior to the earlier groping attempts. Later literary movements - Shaseibun, Naturalism and the Shirakaba school - adopted it as necessary to their aim of realistic portrayal. As these younger writers had not grown up during the period when the old styles were emphasized, they were able to write in the colloquial without hesitation. Outside of literature, Genbunitchi gradually spread in education after 1900, and in newspapers a decade later. Kanbun continued in official documents until 1946, but was then replaced by colloquial style. Chapter Four: There were three other movements without which Genbunitchi could not have been achieved - the script reform movement., the movement for a standard language, and the establishment of punctuation. It was impossible to have a simple style and a difficult, unpunctuated script; moreover, the many dialects in Japan meant that even Genbunitchi style would not be understood unless it were based on a standard form of the Japanese language. Chapter Five: Genbunitchi was not achieved without difficulty. The two major problems were the bitter opposition of conservatives - which found expression in sporadic attacks and in the hotly-fought controversy in "Bun" in 1889 - and the question of which of the many colloquial terminations to use in writing. Each termination was tried, until finally " de aru" became the standard. Conclusion: The Genbunitchi movement was partly social and partly literary, each aspect being dependent on the other. It was essentially a reform resulting from contact with the West, and was one of the most outstanding aspects of the Meiji period.