Samurai Warriors 3 - Ginchiyo's Story 4 - Battle of Kuzegawa

In this battle you will fail if Mitsunari, Sakon, or Motochika die. I'm assuming they didn't make it where you fail if anyone dies, like it was in SW2 for this stage, because even Koei realized your allies can't survive worth a damn. Luckily all the commanders tend to have some officers around them, so they'll die first before they do which gives you some time to run and save them. Which is basically what you do until they're all cleared of enemies, then you have to go deal with Tadakatsu and the remaining enemies.