"Section Chief Kosaku Shima" is a business manga series that delves into the corporate world of Japan, focusing on the professional and personal life of its titular character, Kosaku Shima. The narrative begins with Shima as a mid-level manager at Hatsushiba Electric, a major electronics company. Over the course of the series, Shima navigates the complexities of corporate politics, strategic decision-making, and the challenges of leadership as he climbs the corporate ladder.

The plot is driven by Shima's career progression, detailing his rise from section chief to higher executive positions. Each arc typically revolves around specific business challenges, such as mergers and acquisitions, product development, market competition, and internal company conflicts. Shima's ability to analyze situations, devise innovative solutions, and lead his team effectively is central to the story. His decisions often have far-reaching consequences, impacting not only his career but also the company's direction and the lives of his colleagues.

Supporting characters include Shima's colleagues, superiors, and subordinates, each contributing to the intricate dynamics of the workplace. Notable figures include his mentor, who provides guidance and wisdom, and various rivals who challenge Shima's strategies and leadership. The series also explores Shima's personal life, including his relationships with his family and the balance he strives to maintain between work and home.

The manga provides a detailed and realistic portrayal of corporate life, emphasizing the importance of strategic thinking, ethical decision-making, and effective leadership. It highlights the pressures and responsibilities faced by executives in a competitive business environment, offering insights into the inner workings of a large corporation. Through its focus on Shima's career, the series presents a comprehensive view of the challenges and rewards of professional advancement in the corporate world.