The history of Okayama is closely intertwined with the construction of its famous castle, around which the modern city grew. Although settlements existed in this area earlier, it was in the 16th century, during the Azuchi-Momoyama period, that Okayama began to form as an important centre. Daimyo Ukita Hideie, a vassal of the powerful Toyotomi Hideyoshi, completed the construction of Okayama Castle in 1597. Due to its distinctive dark colour, the castle earned the nickname "Ujo" — Crow Castle.
A key role in the rise of Okayama was played by its strategic location and political stability. The city is situated on a fertile plain at the confluence of rivers flowing into the Seto Inland Sea, which facilitated the development of agriculture and trade. After the Battle of Sekigahara in 1600, power passed to the Ikeda clan, who ruled the region throughout the Edo period (1603–1868). It was under their wise administration that Okayama transformed into a prosperous castle town, becoming the political and economic centre of Bizen Province.
In its early period, Okayama was renowned not only as a military and administrative centre but also as a hub of culture. The rulers from the Ikeda clan were patrons of the arts. In 1700, they completed the creation of the magnificent Korakuen garden, which is considered one of the Three Great Gardens of Japan today. The city's economy relied on the trade of rice grown in the surrounding fields and the development of crafts, such as the production of famous Bizen style ceramics. The city attracted merchants and artisans from all over the country, contributing to its growth and prosperity.