The Collapse of Baekje and the Call for Japanese Aid

In 660 CE, the once-powerful Korean kingdom of Baekje faced annihilation. The Tang Dynasty, allied with the rising Silla kingdom, had crushed Baekje’s armies, captured its king, and occupied its capital. Desperate, Baekje’s surviving loyalists turned to an unlikely savior: Japan.

Led by the nobleman Gwisil Boksin, Baekje’s remnants dispatched envoys—including the high-ranking official Sapyeong Gwiji—to the Japanese court. Their mission was twofold: to beg for military reinforcements and to request the return of Prince Buyeo Pung, who had been living in Japan as a political hostage. The envoys arrived in October 660, bearing a grim gift: over a hundred Tang soldiers captured in guerrilla raids.

Japan, then under the rule of Empress Saimei, saw an opportunity. Fresh from the success of the Taika Reforms, which centralized imperial power, the Japanese court was eager to flex its military might. Saimei’s de facto ruler, her son Prince Naka no Ōe (later Emperor Tenji), viewed the Baekje crisis as a chance to expand Japanese influence in Korea.

The Japanese Expedition and Its Disastrous Outcome

Empress Saimei initially planned to lead the expedition herself—a bold move, though not unprecedented given Japan’s legendary warrior-queen, Empress Jingū. But fate intervened: Saimei died in July 661, forcing Prince Naka no Ōe to delay the campaign while he assumed the throne as Emperor Tenji.

By 663, Japan was ready. A fleet of 27,000 soldiers, commanded by generals like Kamitsukeno no Kimi Wakako, sailed for Korea. Their mission: break the Tang-Silla siege of Baekje’s last stronghold, the fortress of Juryu. Meanwhile, Tang forces, led by the shrewd general Liu Rengui, had already fortified their positions.

The two sides clashed at the Battle of Baekgang (known in Chinese records as the Battle of Baijiang). Despite outnumbering the Tang navy with over a thousand ships, the Japanese fleet was outmatched. Tang vessels were larger, better organized, and equipped with devastating fire arrows. As Japanese ships burned, chaos spread. The Tang chronicles grimly noted: “Smoke and flames scorched the heavens; the sea turned red.”

The Aftermath: A Turning Point in East Asian History

The defeat was catastrophic. Japan lost hundreds of ships and thousands of men, including the celebrated warrior Kibitsuhiko. Baekje’s last hope crumbled as Juryu fell. Prince Pung fled to Goguryeo, while his followers surrendered.

For Japan, the battle marked the end of its ambitions in Korea. The defeat forced a dramatic shift in foreign policy: instead of military expansion, Japan focused on domestic reforms and coastal defenses, wary of a Tang invasion that never came.

For Tang and Silla, the victory was transformative. With Baekje gone, Goguryeo—already weakened by internal strife—fell in 668. The Korean Peninsula was now divided between Tang-controlled territory and a Silla-dominated south, reshaping East Asia’s balance of power.

Legacy: Lessons from a Forgotten War

The Battle of Baekgang is often overlooked in Western histories, but its repercussions were profound. For Japan, it was a humbling lesson in overreach. For Korea, it marked the beginning of Silla’s dominance. And for Tang China, it was a triumph that secured its hegemony—at least temporarily.

Perhaps the most enduring lesson lies in the failures of Baekje’s resistance. Plagued by infighting—most notably the fatal rivalry between Gwisil Boksin and the monk Dochim—the Baekje loyalists fractured when unity was essential. As Liu Rengui later reflected, “War is won by harmony.” Their disunity doomed them, a cautionary tale for any nation on the brink.

Today, the “Great Tang Pacification of Baekje Pagoda” still stands in Buyeo, South Korea—a silent monument to a war that changed the course of history.