Photo: Fort Marune
On the eve of the Battle of Okehazama, Matsudaira Motoyasu (Tokugawa Ieyasu) attacked Fort Marune. The commander of Fort Marune, Sakuma Morishige was killed in action. The assault was successful, but the Matsudaira did suffer some casualties as well.
First source will look is Owada Tetsuo's Okehazama no Tatakai. On pages 206-207 Owada listed seven main samurai who were KIA.
Matsudaira Settsu no Kami Korenobu
Matsudaira Kozuke no Suke Masatada
Matsudaira Kiheiji Munetsugu
Matsudaira Gorobei Tadayoshi
Kato Jingorobei Kagehide
Kuwata Tadachika's Okehazama*Anegawa no Eki has all the seven listed above as well (pp. 183-191). However, Kuwata has four others listed as KIA that are not included in Owada's book.
Matsudaira Denichiro Shigetoshi
Kouriki Shinkuro Shigemasa
Kakei Matazo Masahisa
Owada did state on page 109 that the Sankouki list Kouriki Shigemasa and Kakei Masahisa as KIA. Also Owada has a list of those who participated in the Fort Marune siege (118-120). One name that did stand was Ebara Magosaburo (p. 120). According to Kuwata, Ebara was KIA.
Nobunaga no tame!