Yoritomo's road to Ishibashiyama began in 1160, when his father Minamoto no Yoshitomo was killed in the failed Heiji Rebellion. Yoritomo, just thirteen years old, was exiled by the Taira clan leader Taira no Kiyomori. For two decades he lived as a political prisoner in Izu Province, devoting himself to Buddhist scripture. During this exile he married Hojo Masako, daughter of the local strongman Hojo Tokimasa, binding himself to a clan that would become his military backbone. When Prince Mochihito issued a call to arms against the Taira in May 1180, Yoritomo finally had his pretext. He summoned potential allies one by one to secret meetings, telling each man, 'I am telling you this because I rely solely on you.' The flattery worked on some. Others scoffed -- one retainer compared Yoritomo's ambitions to 'a mouse trying to catch a cat.'

Yoritomo's uprising began not at Ishibashiyama but ten days earlier, with a midnight raid on Yamaki Manor. His target was Yamaki Kanetaka, the Taira-appointed deputy governor of Izu who had pushed the Hojo out of power. Yoritomo timed his attack for the night of the Mishima Shrine festival, when many of Kanetaka's retainers would be away at the celebrations or drinking at a riverside inn. When his adviser suggested taking a side road to avoid festival crowds, Yoritomo refused: 'This is the beginning of our uprising, and we shouldn't use a side road.' The Sasaki brothers, delayed by flooding, arrived exhausted on the day of the attack, and Yoritomo wept with gratitude. That night, his forces stormed the manor, killed Kanetaka, and set the buildings ablaze. The flames were the signal Yoritomo had been watching for from a distance -- proof that his rebellion had begun.

Even with Yamaki defeated, Yoritomo could muster only 300 cavalry. Critical reinforcements from the Miura clan never arrived -- heavy rains had flooded the Sakawa River, cutting them off. When the Taira dispatched Oba Kagechika with 3,000 horsemen, Yoritomo was pinned on the slopes of Ishibashiyama with no escape route and no reserves. The battle was swift and devastating. Yoritomo's small force was overwhelmed, and the survivors scattered into the dense forests of the Hakone Mountains. Yoritomo himself fought with bow and arrow during the retreat, but the situation was hopeless. His loyal retainer Doi Sanemitsu, whose territory this was, made a desperate proposal: he would hide Yoritomo alone while everyone else dispersed to fight another day. They parted in tears, not knowing if they would meet again.

What saved Yoritomo was an act of mercy from the opposing side. As the Oba army combed the mountains, a Taira samurai named Kajiwara Kagetoki found Yoritomo's hiding place but chose to conceal it. He led the search party away, insisting there were no footprints on that particular mountain and pointing them toward a different slope. Legend places this episode at the Shishido Cave in what is now Yugawara, named for a bird that flew suddenly from the cave mouth, convincing the pursuers that no one could be hiding inside. Yoritomo eventually reached Hakone Shrine, where the head priest Gyojitsu sheltered him. From Cape Manazuru, Yoritomo fled by sea to the Boso Peninsula in Awa Province. Today, a shrine called Sanadaraisha stands on the battlefield site, and much of the surrounding hillside is covered by orange groves -- a tranquil landscape that belies the desperation once felt here.

Yoritomo's defeat at Ishibashiyama was total, but it was not final. Reuniting with the Miura clan and other allies in Awa Province, he marched north through the Boso Peninsula, gathering warriors as he went. By the end of September 1180, his army had swelled to tens of thousands. On October 6, he entered Kamakura. Weeks later, at the Battle of Fujigawa, he decisively defeated a Taira force sent from Kyoto. The commanders who had beaten him at Ishibashiyama met grim ends: Oba Kagechika was executed, and his ally Ito Sukechika committed suicide after capture. Yoritomo went on to destroy both the Taira clan and his rivals within the Minamoto, establishing the Kamakura Shogunate -- the first military government in Japanese history. The feudal system he set in motion would endure until the 17th century, all of it traceable to a rainy hillside where 300 riders stood against impossible odds.