Battle of Yamazaki
Toyotomi Hideyoshi (20,000) vs. Akechi Mitsuhide (10,000)
Learning of the death of Oda Nobunaga at the hands of Akechi Mitsuhide, Hideyoshi quickly signed an armistice with the Mori and raced back to the Kyoto region. Akechi, who had failed to gather any support beyond those familes already loyal to the Akechi, was confronted at Yamazaki on 2 July. His troops failed to take the locally important Tennôzan and were routed when flanked after Hideyoshi's army forced a crossing of the Enmyôji River. Mitsuhide himself was killed attempting to flee to Sakamoto Castle, which fell soon afterwards to Hori Hidemasa. Yet, as fate would have it, Oda Nobunaga himself was killed by Akechi Mitsuhide just days later, and the Uesugi would be granted a reprieve.
KIA: (Akechi, in the immediate aftermath) Akechi Mitsuhide, Saito Toshimitsu.
KIA: (Uesugi) Tadanume Yasushike, Takemata Yoshitsuna, Yoshie Kagesuke, ect...
Sources
Berry, Mary Elizabeth. Hideyoshi. Cambridge, Mass.: Harvard University Press, 1982
Bryant, Anthony. Sekigahara 1600. Osprey Military 1995
McCullough, Helen C. The Tale of the Heike. Stanford 1988
Bessatsu Rekishi. Tokuhon #85 Sengoku no Kassen. Japan: Shin Jinbutsu Ôrai Co., 1998
Rekishi Gunzô. Shirizu #5 Takeda Shingen. Japan: Gakken, 1999
Rekishi Gunzô. Shirizu #8 Uesugi Kenshin. Japan: Gakken, 1999
Rekishi Gunzô. Shirizu #49 Môri Senki. Japan: Gakken, 1997
Rekishi Gunzô. Shirizu #51 Sengoku no Kassen. Taizen Japan: Gakken, 1997
Sadler, A. L. The Maker of Modern Japan. Tuttle 1989
Sato, Hiroaki. Legends of the Samurai. Woodstock, New York: The Overlook Press, 1995