"Sengoku Gaiden Okehazama Senki" is a historical manga that delves into the events surrounding the Battle of Okehazama, a pivotal conflict in Japan's Sengoku period. The narrative centers on the rise of Oda Nobunaga, a young and ambitious daimyo, as he seeks to consolidate power and challenge the dominant Imagawa clan. The story begins with the Imagawa Yoshimoto, a powerful warlord, leading a massive army to Kyoto, aiming to assert his dominance over the region. Nobunaga, despite being vastly outnumbered, devises a bold and unconventional strategy to counter the Imagawa forces.

The manga portrays Nobunaga as a cunning and visionary leader, contrasting with the traditional and overconfident Yoshimoto. Nobunaga's key retainers, including Hirate Masahide and Kinoshita Tokichiro (later known as Toyotomi Hideyoshi), play significant roles in supporting his ambitions. The narrative builds tension as Nobunaga prepares for the decisive battle, emphasizing his tactical ingenuity and willingness to take risks. The Battle of Okehazama itself is depicted with intense action and strategic maneuvering, highlighting Nobunaga's use of terrain and weather to outwit the Imagawa forces.

The aftermath of the battle marks a turning point in Nobunaga's rise to power, as his victory over Yoshimoto establishes him as a formidable figure in the Sengoku period. The manga also explores the political and social dynamics of the era, including alliances, betrayals, and the shifting loyalties of samurai clans. Through its detailed portrayal of historical events and characters, "Sengoku Gaiden Okehazama Senki" offers a compelling exploration of one of Japan's most significant military conflicts and the figures who shaped its outcome.