Kenshin's forces attacked him in waves, in a devastating ingenious kuruma gakari ‘winding wheel’ formation, in which every unit was replaced by another, as it became weary or wounded. The Uesugi vanguard, led by one of Kenshin’s Twenty-Eight Generals, Kakizaki Kageie, tore through the Takeda like a chainsaw. Shingen’s commanders fell, one by one. Seeing that his pincer plan had failed, Yamamoto Kansuke took up a long spear and charged alone into the mass of Uesugi samurai. He suffered more than 80 bullet wounds before retiring to a nearby knoll to commit seppuku.
Eventually, Uesugi’s forces penetrated the Takeda command post, and one of the most legendary single combats in Japanese history ensued. Kenshin himself burst into the headquarters, taking Shingen by complete surprise. Unable to draw his sword in time, Shingen fended off Kenshin’s fierce mounted sword slashes with his tessen iron signalling war fan, in one-on-one hand-to-hand combat. He received three cuts on his body armour and seven on his war-fan before one of his retainers, Hara Osumi-no-Kami, speared Kenshin's mount and drove him off. The site of this encounter is now known as the ‘three sword seven sword place.’
Meanwhile, Masanobu's stealth force had reached the top of Saijoyama and, finding the Uesugi position deserted, hurried down the mountain to the ford, taking the same path they had expected to find the fleeing Uesugi on. After desperate fighting, the numerical superiority of Masanobu 12,000 men punched its way through the 3000 warriors that Kenshin had prudently left behind to defend his rear. Just in time, Masanobu's samurai pressed on to aid Takeda's main force, falling on the rear of Kenshin's army, and driving them into and across the Chikuma River. Many Uesugi drowned. Others were cut down by the Takeda. Shingen was saved.
Because the Takeda were the last army on the field, they had nominally won the day, but it was a Pyrrhic victory at best. A ten percent mortality rate was typical for a Sengoku samurai battle, but at the fourth battle of Kawanakajima, Kenshin's army suffered a devastating 72 percent casualty cost of 3000 men, and the Takeda ‘victors’ lost 62 per cent, or 4000 soldiers, including several of Shingen’s most able generals, his younger brother Nobushige, his great uncle Murozumi Torasada, and Yamamoto Kansuke. One of the biggest and bloodiest battles in Japanese history had ended in another draw.
On the morning of the following day Kenshin sent three of his generals to burn what remained of their encampment on Saijoyama. Shingen, his army weakened, made no attempt to stop them, nor to interfere with Kenshin's subsequent withdrawal back to Echigo province.
After the battle, Shingen uncovered two plots on his life, the first from his cousin Katanuma Nobumoto, and the second, a few years later, from his own son Yoshinobo, both of whom he ordered to commit seppuku.
The Tiger and the Dragon met for the fifth and final time on the plain of Kawanakajima three years later. They skirmished for two months, and then withdrew.
Although rivals for more than fourteen years, Shingen and Kenshin were known to have exchanged gifts a number of times, most famously when Shingen gave away a precious sword, which he valued greatly, to Kenshin. In 1570, a number of Hōjō clan daimyô boycotted salt to Shingen’s Kai province. When Kenshin heard of the blockade problem, he secretly sent him supplies, and a letter. My ideals are not your ideals; your desires are not my desires... but wars are to be won with swords and spears, not with rice and salt.
He concluded with a challenge for Shingen to prepare his best forces to meet again on the battlefield, an example of noble chivalry for his and all time.
Shingen, a veteran of over forty campaigns and one of the first warlords to widely integrate firearms, was himself killed by a gunshot wound. On his deathbed he commended Kenshin as an honorable warrior, and instructed his son to rely upon him. Upon hearing of his death, Kenshin dismissed his retainers’ advice to attack the Takeda as childish, and wept aloud at the loss of so worthy an adversary.
‘Even a life-long prosperity is but one cup of sake;
A life of forty-nine years is passed in a dream;
I know not what life is, nor death.
Year in year out-all but a dream.
Both Heaven and Hell are left behind;
I stand in the moonlit dawn,
Free from clouds of attachment.’
Uesugi Kenshin’s Death Poem, five years later.