Well, this film hardly feel realistic historically, because it clearly choses a side from a battle 400 years ago, and yeah, Troy of course tell his story from the side of the achaeans, but both sides fight for good reasons
This is literally pro-ishida from start to finish, he is the hero, young, handsome, competent, fair in justice, a men with valor, honor, respect an love, yes, he form a bond with the most awesome women ninja warrior. Ieyasu is the polar oposite to that, you will feel disgust when you see him.
You have to love Ishida and also to hate nasty Ieyasu.
I'am no japanese expert, but is difficult to explain both men actions if not for ambition and also competency in both sides.
Long movie but watchable, because Japan is beautiful, but the story is kind of a fairy tale of the hero Ishida, and that becomes a little stale and boring kind of fast, because Ishida is just too perfect, and is not an interesting character.