In the Iki Island DLC in Ghost of Tsushima, you’ll come across Monkey Sanctuaries. To begin the mini rhythm game, interact with the mat to play the flute. You will need to keep the pitch between the two lines by using the motion controls.
Raider’s Promontory
After playing the flute, you’ll receive the Charm of Mashira’s Protection. With this charm whenever using the down arrow, your Perfect Parry and Perfect Dodge windows are extended for a limited time. Healing costs 1 additional Resolve.
Saruiwa
This sanctuary can be found southeast of Saruiwa on the very top of a the rock mountain. After playing the flute, your Charm of Mashira’s Protection will improve.
Buddha’s Footprints
This sanctuary can be found west of Buddha’s Footprints. After playing the flute, your Charm of Mashira’s Protection will improve.