Chen Yan, a modern history researcher, unexpectedly found himself in Yizhou in the 5th year of the Zhongping Dynasty, which coincided with Liu Yan's first entry into Shu. He was hampered by local powerful forces inside and invaded by the remnants of the Yellow Turbans outside, and the foundation of his political power was crumbling. Relying on his familiarity with the situation in the late Han Dynasty, he found opportunities in the troubled times and joined Liu Yan's army.
Chen Yan gave up on useless efforts and first helped Liu Yan to clarify the official administration, divide the sharp contradiction between the local gentry and the Dongzhou soldiers, and stabilize the rear of Yizhou; then he offered suggestions to train local warriors, improve ordnance, personally followed the army to quell the rebellion in Bajun, and used strategies to subdue Zhang Lu, successfully guarding the Hanzhong main road.
When Yizhou had sufficient food and grass and soldiers and armor, he once again advocated the strategy of "conquering the Qiang and Di in the west and pacifying the Yi and Yue in the south" to quietly accumulate national power. From then on, from staying in Bashu to quietly observing the changes of the times, to waiting for the opportunity to go east to compete with Jingxiang, and then to contending with the two major forces of Cao Cao and Sun Quan, Chen Yan used his mortal wisdom to assist Liu Yan and his son to make camp step by step, and in the chaos of the late Han Dynasty, he forcibly opened up a different path to the unification of the world.
