Most of what we know about Yasuke fits on a single page of a diary. On the 11th day of the 4th month of Tensho 10 — May 11, 1582 in the Gregorian calendar — a court official named Matsudaira Ietada (松平家忠, Matsudaira Ietada) wrote that Oda Nobunaga (織田信長, Oda Nobunaga) had passed through the province of Kai (甲斐, Kai) accompanied by a retainer described as a black man. The entry is brief, almost offhand. It does not explain who Yasuke was or where he came from. By May 1582, apparently, such explanation was no longer necessary.

Yasuke had arrived in Japan in 1581 as the attendant bodyguard of Alessandro Valignano, an Italian Jesuit missionary who had been working to expand the Catholic mission throughout Asia. Yasuke's precise origins remain unknown. The chronicle of Nobunaga known as the 信長公記 (Shinchokoki, Chronicle of Lord Nobunaga) describes him as powerfully built, approximately in his mid-twenties, with physical characteristics consistent with Sub-Saharan Africa. Some modern scholars have suggested a connection to the Dinka people of present-day South Sudan based on his described height and build; others have proposed Mozambique. None of these hypotheses can be confirmed.

What is documented is the reaction to his arrival. When Valignano brought Yasuke before a crowd in Kyoto, the spectacle was unprecedented — a black man had simply never been seen in Japan. According to the account of Jesuit missionary Luis Frois, so many people pushed forward to see Yasuke that several were killed in the crush. Nobunaga heard about the commotion and summoned him. The warlord reportedly had Yasuke scrubbed with a wet cloth, convinced that his skin color was paint or ink. Satisfied that it was not, Nobunaga laughed and decided he wanted this remarkable man in his service.

Nobunaga gave Yasuke a Japanese name — likely derived from the Portuguese "Yacobo" or "Jacob" — along with quarters in Azuchi Castle (安土城, Azuchi-jo), a stipend, and a katana. These were not gestures of curiosity. They were the formal marks of samurai status. Yasuke was approximately 182 centimeters tall at a time when average male height in Japan was closer to 155 centimeters. He would have been physically imposing by any standard of the era.

The inspection tour of Kai in May 1582 was itself a moment of triumph for Nobunaga. The Takeda clan (武田氏, Takeda-shi) had been among his most feared opponents for years — a warrior lineage famous for its cavalry and its generals. Their destruction in the spring of 1582 felt like a final obstacle removed. Nobunaga was closer to unifying Japan under his control than any warlord in a century. Yasuke walked beside him through this conquered landscape, a man whose origin and journey to that moment were incomprehensible to everyone around him, recorded in a diary entry that treated his presence as unremarkable.

Five weeks later, everything ended. On June 21, 1582, Nobunaga was resting at the Honno-ji (本能寺, Honno-ji) temple in Kyoto when his general Akechi Mitsuhide (明智光秀, Akechi Mitsuhide) surrounded the building with troops and turned against him. The 本能寺の変 (Honnoji no Hen, Honnoji Incident) is one of the most dramatic betrayals in Japanese history. Nobunaga died in the burning temple, aged 47.

Yasuke fought in the defense of Nobunaga's son Oda Nobutada (織田信忠, Oda Nobutada) until Nobutada too was dead. Afterward, Akechi Mitsuhide's forces captured him. According to the sources, Mitsuhide looked at Yasuke and declared that he was "a beast and not a man" and therefore not worth killing. He sent him back to the Jesuit mission house unharmed. This was the last entry in Yasuke's historical record. He simply disappeared. Whether he remained in Japan, returned to Africa, or traveled elsewhere, no document records it.

Yasuke represents something that Japan was, briefly, on the verge of becoming. Under Nobunaga, Japan had been engaging with the wider world in ways that would have been unthinkable a generation earlier. Jesuits moved through the country. Foreign goods and ideas arrived at the ports. A man from Africa could rise to samurai rank not through conquest but through merit and a warlord's personal regard. After Nobunaga, that openness contracted. Hideyoshi issued anti-Christian edicts. Ieyasu formalized isolation. The doors closed for two hundred years. No foreigner would hold samurai rank again for centuries.

The Ietada Diary entry for May 11, 1582 is the clearest window we have into Yasuke's life — dry, factual, and somehow quietly astonishing. An African man, walking through a conquered Japanese province in the spring, beside the most powerful warlord in the country, documented as a normal part of the day. Five weeks from the end of everything.