Conversations with the Khan 3 is one of the Conversations with the Khan records, left by locals during the Mongol invasion. You find it at Ogawa Dojo in Izuhara, and it counts toward the Avid Reader trophy.
Go to Ogawa Dojo in Izuhara and look for the paper or scroll to read. Ogawa Dojo is a Mongol-held territory, so expect to fight or sneak past guards before you can search it.
Also at Ogawa Dojo: the Mongol Artifact Bankhar Dog and 3 Sashimono Banners you get for liberating it.
Bankhar Dog
Bankhar Dog is one of the 50 Mongol Artifacts, pieces of the invaders' culture and warfare you can study. It sits at Ogawa Dojo in Izuhara, and finding 20 artifacts counts toward the Know Your Enemy trophy.
Aaruul
Aaruul is one of the 50 Mongol Artifacts, pieces of the invaders' culture and warfare you can study. It sits at a camp south of Izuhara Clearing in Izuhara, and finding 20 artifacts counts toward the Know Your Enemy trophy.
Adachi Dragon Mask
Adachi Dragon Mask is a New Game+ mask sold by Baku the Voiceless for 5 Ghost flowers. It does not exist in a first playthrough.
Adak Tree
Adak Tree is one of the 50 Mongol Artifacts, pieces of the invaders' culture and warfare you can study. It sits at Yoichi's Crossroads in Izuhara, and finding 20 artifacts counts toward the Know Your Enemy trophy.