The day before 天王寺 (Tennoji), the 豊臣 (Toyotomi) cause had already taken a severe blow. At 道明寺 (Domyoji) on June 2, fog had separated the Osaka southern forces and 後藤基次 (Goto Mototsugu), one of the finest generals in Japan, had died performing 切腹 (seppuku) in the field after being shot down facing an army nine times his size. Now, on June 3, the Osaka commanders gathered what remained of their strength for a single, final, all-or-nothing offensive.

The Toyotomi army numbered roughly 54,000 to 60,000 men. Against them stood 徳川家康 (Tokugawa Ieyasu)'s force of approximately 150,000 to 155,000. The math was always going to lose. But a battle does not run on math alone, and 真田信繁 (Sanada Nobushige) — the man history would remember as 真田幸村 (Sanada Yukimura) — understood that a single decisive blow at the right place could still change everything. He aimed that blow directly at Ieyasu himself.

Nobushige's real name was 信繁 (Nobushige). The name 幸村 (Yukimura) emerged in the popular fiction and drama of the 江戸時代 (Edo Jidai), the Edo period, where he became the idealized image of the defeated but noble samurai — so beloved by the public that the romanticized name eventually eclipsed the real one. At 天王寺 (Tennoji), he was 48 years old, a man who had spent the previous 14 years in exile at 九度山 (Kudoyama) after backing the losing side at 関ヶ原 (Sekigahara). This battle was his first chance to fight in over a decade.

From 茶臼山 (Chausuyama) hill, Nobushige commanded his 7,000 samurai in their famous 赤備え (akabusho) — red lacquered armor — a sight that had terrified opponents in every battle the Sanada fought. He led the charge downhill into the Tokugawa left flank commanded by 松平忠直 (Matsudaira Tadanao). The assault was so violent that Matsudaira's line buckled. 徳川家康 (Tokugawa Ieyasu), age 72, personally rushed reserves to fill the gap. According to some accounts — reported in chronicles but impossible to fully verify — Nobushige's charge penetrated so far that Ieyasu was within sight of the 赤備え (red armor) and at least considered withdrawing from the field. Ieyasu was reportedly wounded by a spear thrust and, by some accounts, had his horse shot under him. Contemporary sources agree the fighting pressed closer to his command post than anything in his long experience.

The legend that Nobushige actually succeeded — that the Ieyasu who survived was a 影武者 (kagemusha), a shadow-double, and the real Ieyasu died that day — spread widely enough in the following years that it is still discussed by Japanese historians. Most dismiss it. But the very existence of the rumor shows how close the assault came, and what it did to the confidence of the Tokugawa camp. A man who had been in power for fifteen years, commanding an army of 150,000, nearly fled from 7,000 men in red armor.

The numbers held. Matsudaira Tadanao's line steadied. Nobushige's men fought until they were exhausted and scattered, most of them dead. When the last charge had spent itself, Nobushige — badly wounded — sat down on a camp stool in the field. A warrior from the Echizen troops, 西尾仁左衛門 (Nishio Nizaemon), approached him. In the Edo-period account, Nobushige looked up and said: "I am 真田幸村 (Sanada Yukimura)." He gave his killer his name, so the man would receive full honor for the act. Nizaemon took his head. The soldier who killed him later said he had never faced a man so dangerous — a tribute from the winning side that became part of the Yukimura legend for centuries afterward.

With Nobushige dead and the assault broken, the 豊臣 (Toyotomi) lines disintegrated. Approximately 15,000 Toyotomi soldiers — nearly half the army — died that day. The following morning, 大坂城 (Osaka Castle) fell. 豊臣秀頼 (Toyotomi Hideyori) and his mother 淀殿 (Yodo-dono) committed suicide inside the burning castle. The 豊臣 (Toyotomi) clan, heirs to 豊臣秀吉 (Toyotomi Hideyoshi)'s unification of Japan, ceased to exist. The 散り際 (chirigawa) — the moment of scattering, of final falling — had come for an entire dynasty, and it looked exactly like a man in red armor charging alone into an impossible fight.