Several of the shrines in The Legend of Zelda: Breath of the Wild are hidden from plain sight. You've got to seek them out specifically if you want to conquer them. The Sasa Kai Shrine is one that you'll have to find by solving the "Sign of the Shadow" quest. Here's how you can complete the quest and get the shrine uncovered after that.
Zelda: Breath of the Wild "Sign of the Shadow" quest: How to solve it
To complete the "Sign of the Shadow" quest, you'll have to speak with Kass on top of the Gerudo Tower in the Gerudo region, which can be found near the southwestern corner of the map. Find Kass there, who will offer up this riddle:
"As light shines from the northwest skies,
From the tower's shadow an arrow flies.
Pierce heaven's light to reveal the prize."
Once you receive this riddle from Kass, the "Sign of the Shadow" quest will be unlocked. You'll need to head out and find the shrine next. First, you'll want to head southeast of where you found the Gerudo Tower. There's a ledge here where you can find a special altar, which is the Sheikah platform you'll need to stand on to unlock the shrine. Climb the tower for a better vantage point. Then use your paraglider to glide down from the tower and to the altar. Stand on the altar.
Next, wait until around 3 p.m. in-game time (from my experience) when the platform has turned red. Shoot an arrow in the sun's direction when it's aligned with the tower. If you did it right, as the video above demonstrates, you'll have unlocked the Sasa Kai Shrine, which completes the "Sign of the Shadow" quest.
Zelda: Breath of the Wild Sasa Kai Shrine: How to beat it
Unlocking the Sasa Kai Shrine and completing the quest is only the first half of what you need to accomplish here. When the shrine rises from the ground, you can still go in it to complete a medium-difficulty test of strength.
There's a guardian inside that you'll need to defeat with a sword or spear. There's not really much strategy required here to finish the fight. Just defeat the enemy and you'll get both a Frostblade weapon and a Spirit Orb as a reward.
Check out more Zelda news and coverage
Find out all there is to know about Zelda: Breath of the Wild, including what to expect from the Wii U version, how to preserve your items, how to beat bosses like the Stone Talus and Lynel, the best recipes for Link and how to take on the game's shrines. You'll also want to find out where all the great fairies in the game and how to use amiibo with your version of Zelda.