Taishan Mansion is one of the Abyssal Domains in Genshin Impact, but you can’t just walk into it. Once you hit the right Adventure Level, which is around 26, you will see it marked on your map near Jueyun Karst.
The doorway is underwater, so to actually get in you will need to figure out a way to lower the water level. To do this, you need to solve a reasonably simple puzzle, but the solution doesn’t exactly jump out at you.
Up first, head to the main monolith marked on the map above by the player icon. Here you will find a locked monolith and some enemies. Kill all the enemies and some more will spawn in. Keep fighting until all the waves are dead. When the last one dies a chest will appear that you can loot, and you will be able to interact with the monolith to lower the water a bit. This will expose the central platform, some stone lanterns, and another locked monolith.
Now, look around for some glowing Geo crystals. Break one with your sword and you will notice a small mote of light floating around you. You need to bring the motes to the lanterns on the central platform. You can find the crystals close to the water at the foot of the cliffs that surround the lake.
Don’t take too long, as the motes will eventually dissipate, but the Geo crystals will respawn pretty quickly. Once you light all three of them, you will be able to interact with the central monolith, lowering the water by one more level. Another chest will spawn near the door of Taishan Mansion, and you can interact with the door to open the Abyssal Domain.
You can farm the following materials in Taishan Manion
- Monday/Thursday – Teachings of Prosperity, Guide to Prosperity, Philosophies of Prosperity
- Tuesday/Friday – Teachings of Diligence, Guide to Diligence, Philosophies of Diligence
- Wednesday/Saturday – Teachings of Gold, Guide to Gold, Philosophies of Gold
- Sunday – All drops
