Sekiro - Doujun and Jinzaemon boss fight

After you complete Doujun quest (assuming you lured Jinzaemon to him and then gave him the red eye you found in the big pond in Mibu village after you obtain the diving skill), head to the Abandoned Dungeon checkpoint and dive in the water to the left side till you find the secret spot . Talk to Doujun, take the stuff in the room and then open the small door. Head back to the checkpoint and rest, then jump back in the water again but don't dive , you well find them on a small land on the left side. They are hard to fight together, try to take them one by one. I won the fight in a weird way, they were fighting a dead person and I just back stabbed one of them and then it was just an easy 1v1, Just luck. BTW, fire from prosthetic arm is good against them. Sekiro™: Shadows Die Twice https://store.playstation.com/#!/en-us/tid=CUSA12047_00