Fort Ohira is a coastal fort in Tsutsu Prefecture that houses the Tsutsu Lighthouse. You pass through it during The Tale of Ryuzo, and its torn banners show what the Mongols did to the clan that lived there.
The fort is part of The Tale of Ryuzo, and it holds one of Izuhara's three lighthouses, so it is worth a return trip if you are hunting lighthouse collectibles.
Adachi Estate
Adachi Estate is the abandoned home of Clan Adachi in Izuhara, where most of Lady Masako's family was murdered. You investigate it in The Tale of Lady Masako and come back during The Husband.
Aoi Village
Aoi Village is a village on the Tsutsu Plains that the Mongols occupy at the start of Act 2. Freeing it gives you the Key of Aoi, one of the keys for The Unbreakable Gosaku.
Arrow Peak Shrine
Arrow Peak Shrine is a Shinto shrine climb in Azamo, Izuhara, dedicated to Inari, kami of agriculture. Reach the summit to earn the Charm of Inari, a major charm: increases the supplies, predator hides, bamboo and yew wood you collect.
Azamo Bay
Azamo Bay is a Mongol-held port town in Azamo Prefecture. You sneak in during The Broken Blacksmith to rescue Taka, then free it for good in Unfinished Business.