In the year 1545, during the latter half of Japan‘s Sengoku Period or ―Age of Warring States‖, the minor samurai Ukida Naoie was assigned thirty men and a small fief in the province of Bizen. His task was to cultivate and defend this small corner of the province from the ambitious and power-hungry lords and bandits that abounded in the Sengoku Period, but Naoie set his sights higher. Given direct control over his thirty men, a mere garrison force of infantry, he used them to conquer and rule over neighboring fiefs in the province. His reputation and his army grew with each victory and before long, Naoie controlled more than a tenth of Bizen and over half of his original thirty men had castles and fiefs to call their own. Naoie himself ruled out of Okayama castle, which he had built for himself, and kept a tight rein on his subordinates through taxation and rotation of service. In 1577 Naoie, after taking over most of the neighboring Matsuda lord‘s forts and province, stormed his own lord‘s keep under flimsy pretenses and seized control of the now expanded Bizen.
Clark, Austin W.
""100 Spears Worth 100 Pieces": The Impact of Ashigaru on Sengoku Jidai,"
The Gettysburg Historical Journal: Vol. 10, Article 3.
Available at: https://cupola.gettysburg.edu/ghj/vol10/iss1/3