The castle gates were open when Tokugawa Ieyasu (徳川家康, Tokugawa Ieyasu) arrived home.

He had ordered them that way before he rode out, and he had nearly not come back.

The sequence of events that produced Ieyasu's worst night began with an act of audacious engineering. Futamata Castle (二俣城, Futamata-jō), perched on a cliff above the Tenryū River (天竜川, Tenryūgawa), had no well inside its walls. Water was drawn by lowering buckets from a wooden watch-tower anchored at the cliff's edge. Takeda Shingen (武田信玄, Takeda Shingen) could not take the castle by storm, but he could think. His engineers constructed large unmanned log rafts and floated them downstream. Repeatedly. Each time, the rafts slammed into the pillars supporting the water-tower. After weeks of this, on December 19 of the Genki (元亀, Genki) third year in the Japanese calendar, the tower's supports gave way and it collapsed into the river below. With no water, the garrison of approximately 1,200 men had nothing left to defend. The castle commander committed seppuku (切腹, seppuku) upon surrender.

When news reached Hamamatsu Castle (浜松城, Hamamatsu-jō), Ieyasu faced a choice that should have been simple. Shingen commanded approximately 30,000 troops — three times what Ieyasu could field even with 3,000 reinforcements from his ally Oda Nobunaga (織田信長, Oda Nobunaga). His goal was not to destroy Ieyasu. He was marching on Kyoto, intending to challenge Nobunaga's dominance over the country. Ieyasu was a nuisance to bypass, not a prize to capture. Every one of Ieyasu's generals delivered the same counsel: stay inside Hamamatsu, let Shingen pass, remain intact.

Ieyasu was 29 years old. He had spent his life proving himself — first as a hostage in the service of the Imagawa (今川, Imagawa) clan, then as a vassal lord scrapping for autonomy. The idea that Japan's most feared general would simply walk past him, treating him as not worth the effort, was more than he could endure. Samurai honor had its own logic, and that logic said: you do not let the Tiger of Kai stroll through your domain.

He rode out.

At the plateau of Mikatagahara (三方原, Mikatagahara), north of Hamamatsu, Shingen's army received the Tokugawa force with a 魚鱗の陣 (gyorin no jin) — the fish-scale formation, layers of soldiers interlocking in a pattern designed to encircle and crush. The Tokugawa force was, in the words of the sources, virtually annihilated. Ieyasu fled the field with only a handful of attendants — accounts vary between five and a dozen.

The open gates held. Before riding out, Ieyasu had ordered the gates of Hamamatsu Castle flung wide and large braziers lit inside. When Baba Nobuharu (馬場信春, Baba Nobuharu) and Yamagata Masakage (山県昌景, Yamagata Masakage), commanding Shingen's vanguard, reached the castle and peered into the firelight, they saw open gates and no defenders scrambling to close them. They suspected a trap — the 空城の計 (kūjō no kei), the empty fort strategy. They halted. A raiding party of roughly 100 Tokugawa foot soldiers and 16 musketeers, led by Ōkubo Tadayo (大久保忠世, Ōkubo Tadayo) and Amano Yasukage (天野康景, Amano Yasukage), struck the Takeda camp that night, causing enough confusion to end the pursuit entirely. Ieyasu had survived by accident, by bluff, and by having nothing left to lose.

In the aftermath, Ieyasu reportedly did something extraordinary. He commissioned a portrait of himself — not a ceremonial image showing him in dignity, but a depiction of his own face at the moment of terror and flight. The painting is known as the 顰み像 (Shikamizō), the grimacing-face portrait: hollow-eyed, hunched, the color gone from his cheeks. It is housed today at the Tokugawa Art Museum (徳川美術館, Tokugawa Bijutsukan). According to tradition, Ieyasu carried it on subsequent campaigns as a deliberate reminder of what defeat looked like — and what it felt like to have ignored his advisors.

The defecation story — that Ieyasu soiled himself during the flight and had himself painted that way — is widely considered apocryphal by historians. The more credible interpretation is simpler and more interesting: a 29-year-old lord who had just made the worst decision of his career decided to hang the evidence somewhere he could not avoid seeing it.

Shingen did not press his advantage in the spring. He besieged Noda Castle (野田城, Noda-jō) in early 1573 and was fatally wounded there — reportedly by a sniper's bullet. He died on May 13, 1573, having never reached Kyoto. His death was kept secret for three years per his dying orders. The army that had nearly destroyed Ieyasu simply... stopped.

Ieyasu had 28 more years. He used every one of them.