How to Start the Quest
Before you can start the quest, you need to complete the first part of the Three Realms Gateway Offering first. Afterward, you need to talk to Yabe, who is a Sangonomiya Samurai, and is on the central platform. He will give you a damaged stone slate. Go to the quest area and drop down the cliff, you should see an opening through the wall. Go inside the room and pull the lever. Now climb back up and you will see a small gap on the wall. Go inside and Paimon will tell you that you need to look for more Stone Slates. Go back to Yabe and he will mark the stone slates on your map.
1st Stone Slate Location
Go to the northwestern island teleport waypoint first and you will see floating platforms in the area. Glide down and you should see some Electro pillars. To the south of the Electro pillars, you will see a gap that will lead to a room. Go inside and you will see the first damaged stone plate on your right, leaning next to the stone pillar. Head north into the room and go to the left wall. You should see the next damaged stone slate near the scrolls on the ground. Now climb up the stairs and you should see another Stone slate on the ground to the right, underneath the rubble.
2nd Stone Slate Location
Now go to the southern island next. You can go to the quest area by dropping down to the underground opening. The first Stone Slate is inside the rectangular structure on your left. You can also find another stone slate on a similar rectangular structure on your right, giving you a total of 2 Strone Slates in the area for you to collect.
3rd Stone Slate Location
Lastly, go to the western island for the last Slate location and do replenish your energy along the way, if you can. When you get to the quest area, you will see a mirror puzzle that you have to solve. Grab a Pyro character like Amber and Melt all the mirrors except for the eastern mirror. Rotate the western Mirror twice and activate the mechanism to get an exquisite chest. Now take a Cryo character like Diona and Freeze all the mirrors except for the southern mirror. Rotate the western mirror once. Activate the Mechanism and then freeze the southern mirror after the light passes through it. Solving this puzzle will give you a Precious Chest and will open up the underground entrance.
Underground Mirror Puzzle
Drop down to the underground area and you will find another mirror puzzle. Start by freezing all the mirrors using a Cryo character. Once you are done freezing all the mirrors, rotate both the eastern and western mirrors once. Activate the mechanism to get a Precious chest and open up another area leading further to the underground. Go down the stairs and replenish your energy if needed. Use your Bokuso Box on the chest to open it. You will find a stone slate behind the treasure chest. The last Stone slate will be on your left, next to the wall.
Insert the Stone Slates
Now go back to the central platform to insert all the Stone Slates in place. You need to move the stone slates to form a pattern. Move the western slate up, then move the southwestern slate up as well. Move the southern slate to the southwest, then move the southeastern slate to the south. Move the eastern slate to the southeast, then move the central plate to the east. Activate the mechanism on your right to complete the puzzle. Jump down to the room and talk to Koyanagi. You will find an extra Stone Slate leaning on the wall to your right.
Close the passage
Get the Stone Slate and use the portal to get back up. Deactivate the Phantasm to close up the passage and insert the last Stone Slate. Activate the mechanism again so it opens up to another room. Defeat the Mysterious Samurai in the room to get a Luxurious Chest. Pull the lever next to the gate to open it and talk to Koyanagi again. Report back to Yabe to complete the world quest.
Summary
The Bunkoku Enigma is a World Quest you can start in the Three Realms Gateway Offering. To solve the mystery of the Stone Slates, you need to complete a series of Stone Slate and mirror puzzles. You will also need to defeat a Mysterious Samurai at the end of the quest. Completing the quest will give you a total of 30,000 Mora, 40 Primogems, three Hero’s Wit, and 40 Light Realm Sigil.