Katayama Market is a small Mongol-held camp on Iki Island, northeast of the Kidafure Battleground. Free it for steel and a minor Legend increase.
Freeing Iki's territories is part of The Butcher Redeemed trophy, which also needs you to beat the Eagle.
Fort Sakai
Fort Sakai is the stronghold Jin's father Kazumasa built on Iki Island, now the Eagle Tribe's main base. It is a story-driven Mongol Territory that you deal with in The Eagle's Cry and The Lightning in the Storm.
Fune's Refuge
Fune's Refuge is a raider hideout on Iki Island run by Fune. You can only get in after the Tale of Iki A Raider's Return, when Tenzo brings Jin there.
Gonoura Cape Hot Spring
Gonoura Cape Hot Spring sits in Gonoura, part of Iki Island, and is one of the game's 20 Hot Springs. Soak there once and Jin's maximum health goes up permanently.
Nakajima Shrine
Nakajima Shrine is a Shinto shrine climb in Gonoura, Iki Island, dedicated to Ugajin, kami of fertility. Reach the summit to earn the Charm of Reflexive Sight, a major charm: press L2 to focus on an enemy who has started to detect you.