Sai Taku, recognized also as Cai Ze, emerges as a pivotal political strategist hailing from the state of Yan. Decades before the central timeline, he rose to prominence as chancellor under King Sho of Qin, forging enduring ties to the kingdom’s governance. Later, he solidified his influence as one of the Four Pillars within Ryo Fui’s inner circle, navigating Qin’s volatile power struggles with calculated precision. Renowned for diplomatic mastery, he commanded Qin’s highest diplomatic authority, specializing in stabilizing ties with his native Yan, where his assignments frequently anchored him. His capabilities, quantified by leadership (92), intelligence (93), and experience (100), mirror a career steeped in shrewd strategy and adaptive statecraft. During the coalition invasion crisis, he orchestrated critical negotiations with the Qi monarch from his eastern post, striving to isolate Qin from broader conflict—a testament to his role as a linchpin in neutralizing external threats. Interactions with peers reveal a tactician who cloaks insight in wit. In one instance, he provocatively contrasted Shouheikun’s military intellect with Moubu’s brute strength under the guise of humor, subtly exposing fissures within Qin’s leadership hierarchy. Such maneuvers underscore his preference for layered communication, using irony to prompt introspection or reveal uncomfortable truths. As Qin pursued unification, he brokered a clandestine meeting between Ei Sei and an unnamed influential figure, aligning his maneuvers with the king’s grand ambitions. This phase of his career highlights his sustained capacity to mold Qin’s alliances and strategic trajectory. Though historical accounts acknowledge his marriage and offspring, familial specifics remain obscured. His evolution from King Sho’s chancellor to Ryo Fui’s confidant and later Ei Sei’s diplomatic envoy illustrates a lifelong fluency in adapting to the currents of political change, cementing his legacy as a perennial architect of Qin’s ascendancy.