Abstract: This article recounts how Harbin Institute of Technology pioneered China’s first fault-tolerant computer, RCJ-1, in the 1970s. Starting with the story behind the seminal book Diagnosis and Fault-Tolerance of Digital Systems, it details the immense challenges overcome under the leadership of Mr. Chen Guangxi. It highlights key innovations like component-level redundancy and parity-based operation monitoring, celebrating the enduring legacy of the “Guangxi Spirit” of perseverance, innovation, and mentorship.