During the opening scene, Laslow and Peri will arrive as new members of your party. For this map, you have two options: you can defeat the boss or escape within 16 turns. The lone dragon vein in the middle of the map can call in an earthquake and destroy all the pots. Ryoma's ninja retainers, Saizo and Kagero, will be guarding the middle area where the dragon vein is located.
Elise will also be out in this battle so the only healer you'll rely on is Felicia. Keep her as a single unit and keep her away from enemy range as much as possible. You can keep her and Azura as your healer units side by side with Azura's passive healing and her Sing ability to make Felicia work again.
There are also two chests (NE – 5000g, NW- Armorslayer) in the two rooms beside Ryoma. He will be guarding the exit so if you can't defeat him, as long as your avatar reaches the escape point, you win. Like the other bosses, Ryoma will not leave his post and won't attack as long as you don't enter his attack range. The same can be applied to the couple of samurai on his side. Alternatively, you can aim for a pincer attack on both sides. Just defeat the apothecary units carrying the door keys and you should be able to get through the doors and defeat the shrine maidens there as well.
The game also specifies that the medicine pots can give one of the three effects below to units within two spaces:
In the other hand, if a poison pot breaks, units within two spaces will get one of the five following negative effects:
That said, always check the pot you're about to destroy to avoid potentially deadly negative effects, especially if there are enemies nearby. Sometimes, you'll have no choice but to break poison pots. When using a paired unit, you can simply switch the inflicted character to wait out the negative effects like halved HP and -5 stats for the turn. You can destroy the pots if you want, to avoid further hassles but take note that some of these pots act as deterrent and will limit some of the enemies' movement. When broken, all units in the field will have max range. Also, Felicia will be most likely targeted by the Shrine Maidens' Silence skill. They can also heal their allies from a great distance using their Wane Festal (shrine maiden on the NW) and warp your units to them using the Entrap spell. (Shrine Maiden on the NE)
At the start of the 7th turn, two squads of archers will appear from the SE and SW. If you can, manage your mid-battle saves especially if multiple units you control gets their max HP halved. This effect lasts for the entire battle and it will be quite difficult to make it through the map if your units are always in the risk of getting one-hit KO'd, especially in Classic mode.
If you decide to move straight in the middle or gone the through both sides, it will be a good idea to wipe out all enemies if you can to earn good exp, due to Conquest's very limited farming options. Just make sure you'll be able to defeat Ryoma by the 16th turn.