It's OK since I got confused because at first you stated cavalry and having a hard time understanding your statement - the reason I had to ask your general's name. If its SSR Ashikaga then you need certain troop types - infantry (at store), then samurai (store), then swordsman (hidden dungeon, chapter 1), then swordsmaster (hidden dungeon, chapter 2). You need to get scrolls from the last stage of reversed history of both chapters in order to have access to the hidden dungeons.
The best way is to ask the general's name so the specifics would be clear. Hehe. Anyway I think you encountered the army I made yesterday - the 3 corsairs and 2 heavy artilleries. I just made that as I thought my troop loss would lessen but the result was the other way around haha. Its always draw or lose when facing Takenaka Hanbei (hatazirushi stage). I always test something just to check the results whether good or bad. But finally got lucky yesterday as I got my first hatazirushi from Oda Nobunaga stage. One more to go XD.
Already reverted to my previous army like 30 mins ago.
i have 1 question more how to unlock harbor building?
check this mononofu guide link
http://harem-battle.club/wiki/Mononofu/Mononofu:Guide