Ieyasu's Iga Flight

Ieyasu's Iga Flight refers to the escape of Tokugawa Ieyasu from Sakai to his home castle of Okazaki in Mikawa Province via Iga and Kōka in the immediate aftermath of the Honnōji Incident of the 2nd day of the 6th month of Tenshō 10 (1582). The honorific Shinkun (Divine Lord) with which this episode is associated reflects the later deification of Ieyasu in Tokugawa mythology, and this flight became a foundational legend of the Tokugawa house. It stands as a pivotal historical episode illustrating how Ieyasu survived a mortal threat in the greatest crisis of the Sengoku period and positioned himself for the eventual unification of Japan.

Background: The Honnōji Incident and Ieyasu's Predicament

In the early hours of the 2nd day of the 6th month of Tenshō 10, forces under Akechi Mitsuhide stormed Honnōji Temple in Kyoto, and Oda Nobunaga perished. At the time, Tokugawa Ieyasu was traveling in the Sakai area (present-day Sakai, Osaka Prefecture), having accepted an invitation from his ally Nobunaga for a sightseeing excursion from Azuchi Castle. His escort was a small group of only thirty to forty intimates including Anayama Nobukimi (Baisetsu), and he had no large force with him.

News of Nobunaga's death reportedly reached Sakai around midday or possibly evening of the same day. Ieyasu's situation was desperately dangerous. If Mitsuhide's forces controlled the Tōkaidō highway, the route home to Mikawa would be cut off. The great Sakai merchant Chaya Shirōjirō Kiyonobu is said to have quickly gathered intelligence and made preparations that assisted Ieyasu's escape.

The Route and Hardships of the Flight

Ieyasu's party departed Sakai and made their way through Kawachi and Yamato into Iga Province, then through Kōka to Mikawa — the route known as the Iga goe (Iga crossing). The path ran through difficult mountain terrain and had to be navigated while Mitsuhide's forces and local strongmen were active throughout the region.

Along the way, Anayama Baisetsu took a separate route and was reportedly killed in a peasant uprising. This was a severe blow to Ieyasu's party. Baisetsu had been a senior retainer of the Takeda clan who had joined Ieyasu's side during the Takeda campaign of Tenshō 10, and the bitter irony was that he met his end during this very flight.

Critical roles in the Iga crossing were played by the ninja communities of Iga and Kōka. Tarao Mitsutoshi, a strongman of Kōka, and Hattori Hanzō, the Tokugawa retainer who led the Iga ninja, are said to have guided and guarded Ieyasu's party; after Ieyasu later achieved dominance over Japan, the Hattori family continued to serve the Tokugawa house.

Return to Okazaki and Preparation for Counter-action

Ieyasu's party is said to have crossed the mountains of Iga and Kōka and then returned to Mikawa either by ship from Shiroko in Ise Province (present-day Suzuka, Mie Prefecture) or overland through Owari to Okazaki Castle. The escape is thought to have taken two to three days.

Upon returning to Okazaki, Ieyasu initially considered raising forces to avenge Nobunaga against Akechi Mitsuhide. However, at the Battle of Yamazaki on the 13th day of the 6th month, Hashiba Hideyoshi moved first, defeating and killing Mitsuhide, and Ieyasu withdrew his forces to watch the situation develop.

Ieyasu's decision at that moment — not to act precipitously, to preserve his strength and wait for the right moment — is regarded by later historians as exemplifying the political essence that would eventually lead to Sekigahara and the founding of the Edo shogunate.

Swords and the Iga Flight

Various traditions have come down regarding the swords Ieyasu carried during this flight. After becoming the ruler of Japan, Ieyasu was a passionate lover of swords, and his castle at Sunpu contained a large collection of celebrated blades he had accumulated over his lifetime.

The tradition that Hattori Hanzō guarded Ieyasu during the Iga crossing has been handed down as an important founding legend of the relationship between the Hattori family and the Tokugawa house. Hanzō was later assigned to guard a gate of Edo Castle, and the place name Hanzōmon in present-day Tokyo derives from his name.

While Iga and Kōka were not themselves famous as centers of sword production, Ieyasu's desperate passage through their mountains illustrates the role of the sword as the ultimate moral and spiritual support for a warrior in life-threatening circumstances. The sword was the soul of the samurai, to be kept on one's person at all times regardless of any difficulty.

The anecdote about Ieyasu's possession of a Muramasa blade — considered ill-omened for the Tokugawa house — is a celebrated story illustrating the inseparable bond between sword and warrior. It is said that Ieyasu deliberately kept the Muramasa and overcame its supposed curse, demonstrating that swords functioned not merely as weapons but as spiritual challenges with which warriors had to come to terms.

Historical Significance and Later Influence

The significance of the Iga Flight in Japanese history extends far beyond its character as a simple escape story.

First, the episode served as proof of the Tokugawa family's legitimacy. Later generations of the Tokugawa house presented Ieyasu's survival of the unprecedented crisis of the Honnōji Incident — through resourcefulness and steadfast courage — as evidence of heavenly mandate. The honorific Shinkun (Divine Lord) arose precisely from this context.

Second, the flight cemented the relationship between the Iga and Kōka ninja communities and the Tokugawa house. Hattori Hanzō and portions of the Iga ninja corps continued to serve the Edo shogunate as intelligence operatives, contributing to the maintenance of shogunal power.

Third, the episode exemplifies the ultimate test for a Sengoku commander: how to conduct oneself amid the power vacuum following the Honnōji Incident. Hideyoshi moved swiftly to destroy Mitsuhide and seize the initiative in the realm. Ieyasu held still, preserved his strength, and brought that accumulated power to bear seventeen years later at Sekigahara. The contrasting approaches of the two men illuminate the essential nature of late Sengoku political strategy.

From the Iga crossing of Tenshō 10 to the founding of the shogunate in Keichō 8 (1603), Ieyasu spent twenty-one years bringing the realm under his control. The Iga Flight stands at the very beginning of that long journey, shining in Japanese history as the moment when the man who would become the founder of the Tokugawa peace chose endurance over precipitate action and lived to fulfill his destiny.