structural:scholar_edition, information:classification
Conflict with Takeda

One of the strongest rulers in the anti-Nobunaga alliance was Takeda Shingen, who used to be an ally of the Oda clan. At the apex of the anti-Nobunaga coalition, in 1572, Takeda Shingen ordered Akiyama Nobutomo, one of the " Twenty-Four Generals " of Shingen, to attack Iwamura castle. Nobunaga's aunt, Lady Otsuya, conspired against the Oda clan, surrendered the castle to the Takeda, and married Nobutomo. From there, the Takeda-Oda relationship declined and Nobunaga started a war against the Takeda clan.

In the same year, Shingen decided to make a drive for Kyoto at the urgings of the shogun Ashikaga Yoshiaki, starting with invading Tokugawa territory. Nobunaga, tied down on the western front, sent lackluster aid to Tokugawa Ieyasu who suffered defeat at the Battle of Mikatagahara in early 1573. However, after the battle, Tokugawa's forces launched night raids and convinced Takeda of an imminent counter-attack, thus saving the vulnerable Tokugawa with the bluff. This would play a pivotal role in Tokugawa's philosophy of strategic patience in his campaigns with Nobunaga. Shortly thereafter, the Takeda forces were neutralized after Shingen died in April 1573.