Generally speaking, you need to decide beforehand what you’re going to do- you can try to take the banners by holding the bridges, you can wait for your enemy to claim the banners and then shove them into the pit and try to keep them away that way, or you can mostly ignore the banners and do your best to clobber Yoshihiro’s army before the 30-turn limit is up, since you only need to deny them one banner. This one is my personal preference, but that’s only because Pokemon gain more Link by knocking out enemy Pokemon than they do by capturing banners and waiting around. If you’re not concerned about boosting your Link ratings as much, you’re safer using one of the other strategies and keeping ahold of the banners.
Fortunately, once you’re aware of the enemy’s Thrust power, all the threats here are obvious- the raw might of the opposing army isn’t hard to see, the pit is fairly blatant, and there are no real surprises on the field. That doesn’t necessarily make the battle easy, but it does make it simpler than some of your recent fights. Keep calm and focus on your chosen strategy, and a win isn’t far off at all.
When the battle concludes, Yoshihiro doesn’t actually seem disappointed at all- instead, you’ve managed to impress him. He seems very upbeat about it, claiming that he will savor his wins all the more now that he has lost once. He congratulates you on the battle you won, and then departs.
After you distribute any Warriors you have gained from this fight, Oichi congratulates you as well, particuarly on having a whole seven kingdoms.
She’s interrupted (not that this is much of a surprise anymore) by Mitsunari, who seems annoyed with how enthusiastic the shy Warrior is about celebrating your victories. The conquering force in the North is brought up again- and the game switches to a semi-video as well. You are informed that Nobunaga, who has been gathering forces in the North, has now amassed a whole eight kingdoms- leaving only two independent fortresses: Terrera and Illusio. Both of these kingdoms are run by Warlords who are known throughout the whole region for their might, supposedly even feared by Nobunaga.
Kiyomasa points out the high degree of danger you could be in if Nobunaga were to capture those last two kingdoms, leaving him with an open channel for reaching you and your empire. Masanori panics a bit about this, prompting Mitsunari to tell you that you need Shingen and Kenshin on your side, to help you deal with this dangerous force.
You are prompted to save immediately after this, concluding your sixth conquest.