When Zhu Yuanzhang, a man of humble origins, rose to become the founding emperor of the Ming Dynasty, he didn’t just bring stability—he brought a tidal wave of political bloodshed. His reign was marked by a series of purges so ruthless and thorough that they remain infamous in Chinese history. Among these, the Four Great Cases of the Hongwu Era—the Empty Seal Case, Hu Weiyong Case, Guo Huan Case, and Lan Yu Case—stand out as the most brutal.

Many rulers before him had cleansed their courts of disloyal officials, from Liu Bang to Zhao Kuangyin, but Zhu Yuanzhang’s approach was exceptionally violent. Why? The answer lies in his past, his paranoia, and his relentless pursuit of absolute control.

The Empty Seal Case: Breaking the Unwritten Rules

It all started in 1376 when Zhu Yuanzhang discovered that local officials brought pre-stamped blank documents to the capital for financial audits. This practice, known as kongyin (空印), was a long-standing bureaucratic shortcut—common since the Yuan Dynasty—to avoid the hassle of redoing reports if errors were found.

To the officials, this was just business as usual. To Zhu Yuanzhang, it was treason.

He saw it as an attempt to deceive the throne and an extension of the corruption that had once driven his family into starvation. His fury led to mass executions: the chief officials were beheaded, while their subordinates were flogged and exiled.

Was this an overreaction? Probably. But to Zhu Yuanzhang, the message was clear: “Just because something has always been done a certain way doesn’t make it right.” Or, as Lu Xun would later put it: “Has it always been this way? If so, does that make it correct?”

The Hu Weiyong Case: No Room for a Prime Minister

In 1380, Zhu Yuanzhang accused his chancellor, Hu Weiyong, of plotting against him. Whether Hu was truly guilty is still debated, but his crime in Zhu’s eyes was clear—he had amassed too much power.

For Zhu, this was déjà vu. He had seen powerful ministers like Toghto and Bayan overshadow Mongol emperors, and he wasn’t about to let history repeat itself. Hu was executed, and thousands of officials were dragged down with him. But that wasn’t enough—Zhu went further, abolishing the position of prime minister altogether.

From that moment on, the emperor would handle all state affairs personally. The Ming Dynasty became the first Chinese empire to abolish the position of chancellor, ensuring that no single official could ever challenge the throne again.

The Guo Huan Case: A War on Corruption—or an Excuse?

By 1385, Zhu Yuanzhang turned his sights on corruption. The target? Guo Huan, a senior official in the Ministry of Revenue, accused of embezzling tax revenues.

At first glance, it seemed like just another anti-corruption campaign. But something didn’t add up. The case implicated thousands of officials across the empire. Could so many people have been involved in the same scheme?

What was really happening was a power struggle over land and taxation. Just a few years earlier, Zhu had introduced the lijia (里甲) system and land registration reforms to tighten state control over local wealth. But the aristocracy and landowners resisted.

By wiping out thousands of bureaucrats and confiscating their wealth, Zhu not only crushed corruption—he eliminated opposition to his economic policies.

The Lan Yu Case: When Generals Become Too Powerful

Lan Yu was no ordinary soldier. He was a war hero, a brilliant general, and the brother-in-law of Zhu Yuanzhang’s late son, Crown Prince Zhu Biao. Under normal circumstances, he should have been untouchable.

But in 1393, Zhu had him executed for “plotting rebellion.” The charge was flimsy, but the reason was clear: the balance of power had shifted.

When Crown Prince Zhu Biao died, Zhu Yuanzhang named his grandson Zhu Yunwen as heir. Lan Yu, a close relative of another royal grandson, was now a dangerous wildcard. If Zhu Yuanzhang allowed him to live, the throne might fall into the wrong hands.

So he purged him. Along with 15,000 others.

The Emperor’s Bloody Gamble

Zhu Yuanzhang’s four great purges weren’t random acts of cruelty. Each served a purpose:

  • The Empty Seal Case destroyed bureaucratic complacency.
  • The Hu Weiyong Case eliminated the chancellorship and centralized power.
  • The Guo Huan Case strengthened imperial control over the economy.
  • The Lan Yu Case ensured military loyalty to Zhu’s chosen successor.

Did it work? In the short term, yes. The Ming Dynasty lasted for nearly 300 years. But his brutality also left a legacy of paranoia, setting the stage for future emperors to rule with fear rather than trust.

In the end, Zhu Yuanzhang won the throne through blood—and he kept it the same way.