Sakai Banners are 30 weathered Clan Sakai flags spread across Iki Island in the Director's Cut. Locals planted them where they beat the samurai years ago; bring them to Tsubaki to unlock dyes for the Sakai Horse Armor.
Iki's raiders put these Sakai flags up where the samurai fell during their failed invasion of Iki fifteen years before the expansion. They are old and torn now, and each one marks a spot of that defeat.
Nakajima Island (on the path to Nakajima Shrine), Smuggler's Run on top of some rocks, a ledge in Cloud Forest, Cloud Forest Temple itself plus a small cliff northeast of it, the south coast of Buddha's Footprints, Saruiwa Overlook (two), north of Lake Nagata, Zasho Bay and Saruiwa.
Yahata Forest, three at Tatsu's Ladder (a small cliff to the east, a hidden cliffside alcove and a rock at the foot of the falls), Katayama Market, Kemono Trail, three at Barrier Cove (northern tip, a cliffside and the water's edge below the cliffs), Thunderhead Cliffs, Fort Sakai (three), Sly Hunter's Forest, Sentinel's Peak, the top of Lone Spirit Falls, Fune's Refuge and a small cave on the south side of Shattered Cliffs near Gonoura Cape.
Fort Sakai, Katayama Market and Sentinel's Peak are Mongol-held, so take them while you are there. Several banners sit on cliffs, so look up and down when the Guiding Wind points you to a rock face.
A Scrawled Message
A Scrawled Message is a written record from the Records of Iki set, left by locals during the Mongol invasion. You find it at a camp south of Lake Nagata on Iki Island, and it counts toward the Avid Reader trophy.
Attached to an Old Crate
Attached to an Old Crate is a written record from the Records of Iki set, left by locals during the Mongol invasion. You find it at a shed northwest of Lone Spirit Fall on Iki Island, and it counts toward the Avid Reader trophy.
Image: Sucker Punch Productions / PlayStationBamboo Strikes
Bamboo Strikes are button-timing challenges where Jin slices a row of bamboo poles. There are 20 in all, 16 on Tsushima and 4 on Iki, and completing them raises your maximum Resolve.
Beware the Tengu-Masked Archer
Beware the Tengu-Masked Archer is a written record from the Records of Iki set, left by locals during the Mongol invasion. You find it at a house in Yahata Forest on Iki Island, and it counts toward the Avid Reader trophy.