The Four-Eye Reef gets its name from the way it looks from above. In the perimeter of the reef’s rocky walls are four circular, eyelike pillars. After you rescue Aryll from the Forsaken Fortress, enemy Warships and wall-mounted cannons appear here.
Treasure Chart #19
Bomb all the Warships and wall-mounted cannons to reveal a chest on the reef’s northwestern eye. Go to a narrow opening in the reef’s rocky wall and walk up the slope and across the top of the wall to its highest point. If needed, play the “Wind’s Requiem” to direct the wind, then use the Deku Leaf to float over to the chest, which contains Treasure Chart #19.
Great Fairy Chart (via Treasure Chart #41)
Find and open Treasure Chart #41 (the Five-Eye Reef [B6]) to pull a chest from the Great Sea near the Forsaken Fortress. The chest contains the Great Fairy Chart, which reveals the locations of every Great Fairy across the Great Sea.