Siege of Odawara (Hard)

As a note for anyone struggling with this, I think the best way to clear it is to actually not attack Odawara directly at all.

At the beginning, use your left side forces to whale on Daidouji Masashige until he surrenders. Ideally we'll hurt him enough on the first turn to get him to surrender, but more likely than not our firepower is too low and he'll stay as an enemy until turn 3 (his active ability, Feint Attack reduces damage for a turn) or 4. Your right side forces should focus on overpowering Hojo Ujifusa (who also annoyingly has an active which reduces damage) and taking Iwatsuki castle. Luckily the right side starts out with a rank 5 Tadakatsu who does wonders in damage, he even starts off with his set, and you don't actually have to kill the heavy cavalry and elite teppo that are with Masashige, they become turncoats with him.

By turn 4, Ieyasu should have taken Yamanaka castle. Ideally around here's where you march your left hand and right hand forces to meet at Hachioji castle, defeating Nakayama Ienori and Kondo Tsunahide, but depending on how well your attacks go you might still be fighting Ujifusa and maybe even Masashige. Even if one side is being held up I would still recommend attacking with the free side (most likely your left) and joining later with your other wing.

Turn 5 annoyingly has night descend upon our forces, removing our range bonus for ranged units. This was when I was able to finally kill Ujifusa in my repeat clear attempt. Once you take Iwatsuki castle I'd recommend building a barn in it to stymie your food loss and allow you to actually build mounted archer later since both Iwatsuki and Hachioji can spawn that unit. Also make sure there's a unit in Iwatsuki castle during this night phase to protect it since Fuma Kotaro will spawn and attack unfairly after you finish turn 7 (possibly later if you're slow at taking Hachioji). He also annoyingly has an active that reduces damage (seeing a trend here?) since you can't directly attack him for a turn, so focus on slaughtering his ninja accompaniment instead. At turn 9 it should become daytime again, and Fuma Kotaro should be attackable, so kill him. Clean up the remaining forces around your castles and spawn a mounted archer while waiting for Masamune to arrive.

On turn 11 Hojo Ujikatsu and Hojo Ujinori should surrender Tamanawa and Nirayama castle, and around here's where Masamune arrives with Date Shigezane and Katakura Kagetsuna. Kill all three to end the mission. Since anything south of Hachioji surrenders by script, you don't actually need to worry about the majority of the battle. Just trust in Hideyoshi's plans.

Hilariously, Hojo Ujinao claims he'll commit seppuku here. He actually doesn't, it's Ujimasa who does so. It doesn't really matter though since he'll die pretty soon after. I used Date Masamune on mounted teppo and Mori Motonari on mounted archer as my deployments, and I placed Toyotomi Hideyoshi on the elite samurai on the right hand side and Maeda Keiji on the horoshu cavalry on the left hand side. I also used Chosokabe Motochika on a spawned mounted archer, but he can be substituted with anyone who has competency with the bow.