Once you reach the Cleansing Defilement objective of the Sacred Sakura Cleansing Ritual world quest, you'll be tasked with solving a barrier puzzle in Araumi's underground ruins. Unrelated to this quest is a separate cube puzzle, which you can find by dropping down into the Araumi ruins and heading to the left.
Solving the cube puzzle allows access to a convenient Teleport Waypoint, along with a direct path to both the Perpetual Mechanical Array boss and the hidden domain, Empty Boat of a Thousand Gates.
How to solve the first Araumi underground cube puzzle
Stand directly in front of the five cubes. From the default cube states, hit them in the following order:
- Bottom left
- Bottom left (again)
- Top right
- Top right (again)
If at any point you mess up this order, simply log out and then log back in to reset the cube patterns.
Completing the puzzle rewards you with a Precious Chest and passageway further down into the ruins. Swim until you find a staircase you can climb (take stamina breaks by sticking to the walls), and there you'll find the second cube puzzle.
How to solve the second Araumi underground cube puzzle
There are five cubes arranged in a straight line. This puzzle is even simpler than the first: just hit the middle block twice.
Another Precious Chest will appear, and the water blocking off the rest of the ruins will submerge.
Keep exploring the ruins to find a Teleport Waypoint, Perpetual Mechanical Array, and the Empty Boat of a Thousand Gates domain.