During the Jisho Juei War (Genpei War), there was a battle between MNAMOTO no Yoshinaka and Taira clan in 1183, and another battle between MINAMOTO no Yoshitsune and MINAMOTO no Yoshinaka in 1184, and Kanehira IMAI was the commander defending the Seta-bashi Bridge for Yoshinaka against MINAMOTO no Noriyori, by removing the planks of the bridge.
治承・寿永の内乱（源平合戦）1183年（寿永元年）に源義仲対平家、1184年（寿永2年）に源義経対義仲の合戦があった際に、源範頼が攻める瀬田橋の橋板をはずして守っていたのが今井兼平。