Editing Tokugawa Ieyasu (section)

===Tōtōmi campaign===
In 1568, Ieyasu besieged the Horikawa Castle in Tōtōmi<ref name="OkazakiOkubotadachika59">{{cite book |title=新編岡崎市史: Sōshū hen Volume 20 of New edition of Okazaki City History |date=1983 |publisher=新編岡崎市史編さん委員会 |location=Okazaki City |page=59 |url=https://books.google.com/books?id=j3VMAQAAIAAJ |access-date=24 May 2024 |language=Ja}}</ref> and captured it in 1569. Ieyasu then ordered Ishikawa Hanzaburo to massacre the castle prisoners and residents, including women and children. It was recorded that around 700 people were beheaded on the banks of the Miyakoda River.<ref name="Horikawamassacre">* {{Cite book|last= Kamefumi Naito|date= 1972  |chapter= 姫街道の今昔 |editor=静岡新聞社 |title= ふるさと百話 |publisher= 静岡新聞社 |volume= 7 |pages= 155–159}}</ref> [[Ōkubo Tadachika]], who witnessed this massacre testified in his personal journal, ''Mikawa Monogatari'', that "... {{sic|both mens and womens can be cut into pieces}}...".<ref>{{citation |publisher=Hosoe town Board of Education |location=Horikawa castle Ruin |language=Ja |title=Mikawa Monogatari}}</ref>

Later the same year, Ieyasu's troops penetrated Tōtōmi Province. Meanwhile, Takeda Shingen's troops captured [[Suruga Province]], including the Imagawa capital of Sunpu. [[Imagawa Ujizane]] fled to [[Kakegawa Castle]], which led Ieyasu to [[Siege of Kakegawa|lay siege to Kakegawa]]. 

Ieyasu then negotiated with Ujizane, promising that if Ujizane surrendered himself and the remainder of Tōtōmi, Ieyasu would assist Ujizane in regaining Suruga. Ujizane had nothing left to lose, and Ieyasu immediately ended his alliance with [[Takeda clan|Takeda]], instead making a new alliance with Takeda's enemy to the north, [[Uesugi Kenshin]] of the [[Uesugi clan]]. Through these political manipulations, Ieyasu gained the support of the samurai of Tōtōmi Province.<ref name="Turnbull-I2"/> Furthermore, Ieyasu also placed the "''Iinoya's trio"'' (Iinoya-Sanninshu) of clans under the command of his trusted vassal, [[Ii Naomasa]].<ref name="shinshiro_iinoya">{{Cite web|url=https://www.city.shinshiro.lg.jp/kanko/hito/iinoya.html|title=井伊谷・井伊家と新城地域|publisher=新城市|access-date=2023-02-26}}</ref> The Iinoya trio were powerful clans that originated from the eastern side of Mikawa who greatly contributed to Ieyasu's expansion during his conquest of the former Imagawa territories in Tōtōmi Province.<ref>{{cite web |author1=Watanabe Daimon |title=徳川家康を遠江で手引きした「井伊谷三人衆」とは、いったい何者なのか |url=https://news.yahoo.co.jp/expert/articles/f996f723c6f02a99afad64fa625469e8c93f47c2 |website=yahoo.co.jp/expert/articles/ |publisher=渡邊大門 無断転載を禁じます。 © LY Corporation |access-date=3 June 2024 |language=Ja |date=2023}}</ref>

In 1570, Ieyasu established [[Hamamatsu]] as the capital of his territory, placing his son Matsudaira Nobuyasu in charge of [[Okazaki, Aichi|Okazaki]].<ref name="Arms">{{cite book|last1=Turnbull|first1=Stephen|title=Battles of the Samurai|date=1987|publisher=Arms and Armour Press|location=London|isbn=0853688265|pages=67–78}}</ref>{{efn|According to the Todai-ki, the castle was originally planned to be relocated to Mitsuke (the site of Kinosaki Castle is said to be), but was changed to Hamamatsu at the request of Oda Nobunaga. It is speculated that Nobunaga did not want the Oda and Tokugawa bases to be too far apart.<ref>{{harvtxt|Shiba|2021|p=190}} quoting {{cite book |last1=Koichi |first1=Abe |date=1997 |title=Shizuoka Prefecture History |chapter=Ieyasu's Conquest of Totomi and the Battle of Mikatagahara |series=General History |volume=2}}</ref>}}