In 1570, during Nobunaga's invasion of Echizen, Azai Nagamasa broke from the Oda alliance, collapsing the pact that bound the two houses. This defection placed Nobunaga's Owari–Kyoto route in danger and forced him to withdraw via Wakasa and Fusakawa.
In 1564 Oda Nobunaga bound his sister Oichi in marriage to Azai Nagamasa, turning a rivalry into an alliance that opened the road to Kyoto. Six years later Nagamasa broke from that alliance, facing a difficult choice between the Oda and his long-standing ties to the Asakura — a decision that placed Nobunaga's army in a pincer crisis and forced a withdrawal from Echizen. The war that followed at Anegawa and Odani extinguished the Azai house, but Nagamasa's line endured through his daughter Chacha, who as Yodo-dono carried the memory of both houses into Osaka Castle itself.
In 1564 Oda Nobunaga sealed an alliance with Azai Nagamasa by offering his younger sister Oichi in marriage. The alliance made travel through Nobunaga's northern flank safer and made advancing toward Kyoto easier. In 1568 Nobunaga entered Kyoto with Ashikaga Yoshiaki under his protection, and Yoshiaki was invested as shogun.
In 1570 Nobunaga invaded Echizen to crush the Asakura clan. Nagamasa faced a difficult choice between his new alliance with the Oda and his long-standing ties to the Asakura. Choosing to keep faith with Asakura, Azai forces threatened Nobunaga's line of retreat, and the Oda army was forced to withdraw hurriedly from Echizen.
Reacting to the Azai defection, Nobunaga joined forces with Tokugawa Ieyasu; in June 1570 the two sides fought at Anegawa. Defeated there, the Azai–Asakura army fell back to defending their own bases.
In 1573 Nobunaga besieged Odani Castle and Azai Nagamasa took his own life. Odani fell, and the Azai house was extinguished as a Sengoku daimyō house. Oichi and her three daughters were taken into Oda custody, and their eldest, Chacha, would later gain political standing at Osaka Castle as Yodo-dono.
Explore the stone walls, hidden moats, and battleground sites Osaka Castle, personally led by Edward Iftody. One historian. Six guests. One investigation.
Book Warrior Monks, a Peasant, and a ShogunThe Azai bloodline didn't end at Odani — it walked straight into the heart of Osaka Castle through Yodo-dono, carrying with it the same oaths, betrayals, and blood debts that destroyed her father. What began as a marriage pact in 1564 didn't finish until the keep itself burned in 1615.
If you'd like to walk the ground where that inheritance finally played out, Warrior Monks, a Peasant, and a Shogun follows that story across the very site where it unfolded.
The Oda–Azai war was the hinge that swung the Sengoku era — and the ground it was fought over leads straight into Osaka Castle’s own history, and into the decade-long siege of the Ishiyama Hongan-ji that followed.
Walk with a historian who lives beside it. Small groups. Osaka Castle every day • English • Max 6 guests
Book Warrior Monks, a Peasant, and a Shogun Call / Text Edward WhatsApp EdwardLast updated: October 2026
Edward Iftody — Osaka Castle’s Resident Historian
Research by Edward Iftody, Osaka-based historian and resident historian at Osaka Castle.
This reconstruction draws on contemporary European accounts, Japanese archaeological research, historical geography, and the surviving physical landscape.