Chugai B examines the pivotal strategic alliance formed in October 2002 between Chugai Pharmaceutical and Swiss giant Roche. Facing constraints in RD funding and global reach, Chugai's President Osamu Nagayama sought a partnership to achieve the firm's ambition of becoming Japan's number one pharmaceutical enterprise while preserving its autonomy. The case examines the unique business model by which Roche acquired a 50.1 equity stake while Chugai retained its management, public listing and corporate identity. This structure created a powerful synergy: Chugai gained exclusive rights to develop and market Roche's innovative products in Japan, while Roche leveraged Chugai's RD pipeline for its global distribution network. The case details how the alliance transformed Chugai from Japan's 10th largest pharma firm into its market leader in oncology and by market capitalization by 2024. It provides a rich context for analyzing how strategic partnerships can bridge resource gaps, foster a 'capability revolution,' and accelerate a company's path to becoming a global innovation powerhouse.