The Collapse of Northern Defenses and a Rebellion’s Momentum

In the bitter winter of early 756 CE, the An Lushan Rebellion reached a pivotal moment as rebel general Shi Siming consolidated control over northern China. After capturing Changshan, Shi’s forces swept through neighboring commanderies – Ye, Guangping, Julu, Zhao, Shanggu, Boling, Wen’an, Wei, and Xindu – with brutal efficiency. Only Raoyang’s steadfast governor Lu Quancheng refused to submit, prompting Shi to lay siege while defeating two relief forces sent by loyalist officials Li Huan and Li Wei.

This military disaster exposed the Tang dynasty’s vulnerability. As contemporary observers noted, “Warfare requires professionalism – irregular forces stood no chance in open battle against trained troops.” Yet the heroic last stand at Changshan by Yan Gaoqing and Yuan Lüqian proved consequential, demonstrating northern resistance potential that would shape Emperor Xuanzong’s strategic response.

The Rise of Military Professionals: Li Guangbi’s Ascent

Recognizing the crisis, Emperor Xuanzong recalled veteran general Guo Ziyi from the northern frontier and tasked him with reorganizing defenses. Guo made a fateful recommendation – elevating the talented Li Guangbi as his deputy. This marked the emergence of one of Tang’s most remarkable military leaders.

Li Guangbi’s background reflected Tang cosmopolitanism at its height. Born to a Khitan chieftain who had joined Tang service, Li represented the rapid sinicization of frontier elites. Fluent in classical Chinese texts like Ban Gu’s Han Shu, he observed Confucian mourning rituals with such strictness that contemporaries remarked: “At this point, what distinction remains between ‘barbarian’ and Han?”

His military career began auspiciously as a Left Langjiang officer (rank 5b), outpacing even Guo Ziyi’s early trajectory. By the Tianbao era (742-756), Li had risen to key northern commands, earning the admiration of famed general Wang Zhongsi who predicted: “The man who will inherit my military methods is none other than Li Guangbi.”

The Double Offensive: Li Guangbi’s Northern Campaign

In early 756, Li Guangbi assumed command of the critical Hedong theater with 10,000 elite troops. His first move demonstrated strategic brilliance – securing Changshan through a combination of psychological warfare and tactical innovation. When captured rebel officer An Siyi provided accurate intelligence about Shi Siming’s movements, Li incorporated this into his defensive preparations.

The subsequent battle showcased Li’s mastery of combined arms. Deploying crossbowmen in rotating volleys and spearmen in disciplined formations, he repelled Shi’s cavalry assaults along the Hutuo River. A daring night raid then annihilated 5,000 rebel reinforcements at Fengbi, forcing Shi into retreat.

Meanwhile, Guo Ziyi arrived with reinforcements, combining forces to create a 100,000-strong army. Their coordinated campaign achieved decisive victory at Jiumen (April 756), killing 4,000 rebels and sending Shi Siming fleeing barefoot after falling from his horse. This triumph sparked uprisings across Hebei, with local militias swelling Tang ranks.

Zhang Xun’s Legendary Defense: The Southern Anchor

While northern campaigns progressed, another epic unfolded southward at Yongqiu, where magistrate Zhang Xun orchestrated one of history’s most remarkable urban defenses. With just 2,000 hastily assembled troops, Zhang repelled 40,000 rebels for over two months through ingenious tactics:

– Fire arrows made from oil-soaked reeds against siege engines
– Sudden sorties targeting disorganized besiegers
– Night raids using ropes to descend unseen from walls

After sixty days and 300 engagements, Zhang’s forces had not only held but captured 2,000 elite rebel cavalry in a counterattack. His defense protected the vital Yongji Canal – the economic lifeline connecting Jiangnan’s wealth to the capital.

Strategic Implications and the Rebellion’s Turning Point

By mid-756, the coordinated efforts of Li Guangbi, Guo Ziyi, and Zhang Xun had achieved remarkable results:

1. Northern Theater: Tang forces controlled most of Hebei, cutting rebel supply lines to the northeast. Local militias now numbered over 20,000.

2. Southern Theater: Zhang Xun’s defense ensured continued revenue flow from the south while tying down rebel forces.

3. Psychological Impact: Rebel morale collapsed as An Lushan reportedly contemplated abandoning Luoyang. His outburst to advisors – “You claimed this would be easy!” – revealed growing desperation.

However, political intrigue at court would soon undermine these gains. The suspicious death of general An Sishun at Geshu Han’s instigation and growing tensions between Geshu and chancellor Yang Guozhong created new vulnerabilities. As Li Guangbi and Guo Ziyi warned from the field: “If the main army advances from Tong Pass now, disaster will befall the capital.”

Legacy of the 756 Campaigns

The battles of early 756 demonstrated several enduring lessons:

1. Professionalism Matters: The contrast between trained armies and militia underscored military specialization’s importance.

2. Adaptive Leadership: Li Guangbi’s incorporation of local intelligence and Zhang Xun’s tactical creativity exemplified effective command.

3. Strategic Patience: As Guo Ziyi argued, sometimes wearing down an enemy proves wiser than seeking quick victory.

Though political decisions would soon lead to the catastrophic defeat at Tong Pass, the campaigns of Li Guangbi and Zhang Xun laid groundwork for ultimate Tang victory. Their stories endure as testaments to resilience, innovation, and the complex interplay between military and political factors in shaping history’s course.