The schism that would split Japan's imperial house for 56 years began with a deathbed compromise in 1272. Emperor Go-Saga, hoping to keep peace between his two sons, insisted that future emperors alternate between their fraternal lines -- one generation from Go-Fukakusa's family, the next from Kameyama's. It was an elegant solution on paper and a disaster in practice. Within decades, two rival factions crystallized. Go-Fukakusa's descendants, known as the Jimyoin-to, took their name from a palace in Kyoto. Kameyama's line, the Daikakuji-to, identified with the cloistered residence of Emperor Go-Uda. Both claimed the Chrysanthemum Throne. Neither would step aside. When Emperor Go-Daigo of the Daikakuji-to made his bid for sole power in 1333, he triggered a civil war that would define medieval Japanese politics.

Go-Daigo's Kenmu Restoration -- his attempt to overthrow the Kamakura shogunate and restore direct imperial rule -- succeeded brilliantly and then failed spectacularly. He destroyed the shogunate in 1333, but his former ally Ashikaga Takauji turned against him just three years later, installing a rival emperor from the Jimyoin-to line in Kyoto. Go-Daigo fled south into the mountains of Yoshino, carrying with him the imperial regalia: the sacred mirror, sword, and jewel that authenticated a sovereign's claim. From this remote mountain refuge south of Nara, he declared his court the only legitimate government of Japan. The Northern Court in Kyoto had the capital, the military backing of the Ashikaga shoguns, and effective control of the country. The Southern Court in Yoshino had the regalia and the principle. Four emperors would reign from this mountain exile -- Go-Daigo until 1339, then Go-Murakami, Chokei, and finally Go-Kameyama -- each maintaining the claim as their territory shrank and their cause grew more desperate.

By 1392, the Southern Court had nothing left to fight with. Emperor Go-Kameyama agreed to surrender the imperial regalia to the Northern Court's Emperor Go-Komatsu, but only on one condition: the old alternating succession would resume, with the throne passing between the two lines on a ten-year cycle. Go-Komatsu accepted. Then he broke his word. He ruled for 20 years, not ten, and when he finally abdicated, the throne passed to his own son -- not to anyone from the Southern line. The betrayal was complete. The Southern Court's dynasty was extinguished as a political force, its remaining descendants scattered into obscurity. The Northern Court's line would produce every subsequent emperor of Japan, straight through to the present day.

History rarely sides with the defeated, but Japan proved an exception. In the centuries after reunification, a growing intellectual tradition held that the Southern Court had been morally right -- that possession of the imperial regalia constituted true legitimacy, regardless of military outcomes. This view gained political force during the Meiji period, when the new government needed to establish the emperor's authority as absolute and unchallengeable. On April 3, 1911, an Imperial decree settled the question: the Southern Court emperors were declared the sole legitimate sovereigns of the 1336-1392 period. The Northern Court's five emperors were officially redesignated as pretenders. It was a remarkable reversal -- the winning side of a medieval civil war retroactively delegitimized by its own descendants. The irony cuts deep: every emperor since 1392 descends from the Northern line, meaning the decree effectively declared the sitting emperor's own ancestors to have been usurpers.

Today, the Yoshino mountains where Go-Daigo held his exiled court are famous for their cherry blossoms -- over 30,000 trees carpet the slopes each spring in clouds of pink and white. The connection between the flowers and the court runs deep. Go-Daigo is said to have loved the mountain's blossoms, and pilgrims and tourists who climb through the groves at Yoshino walk through the same landscape that four emperors once called their capital. Little physical evidence of the Southern Court survives, but the political legacy endures in one of Japanese history's most paradoxical facts: the side that lost the war won the argument, and the dynasty that was extinguished was declared the only one that ever truly reigned.