Amenoma Kageuchi is a new four star weapon available in Inazuma in Genshin Impact.
Before you can get the blueprint to craft such a sword, you have to go through quite a lengthy quest.
First of all, you need to find four old stone slates before you get the The Farmer’s Treasure quest.
Here’s how you can unlock the Amenoma Kageuchi in Genshin Impact.
All four old stone slate locations
Before you look for the old stone slates, you should meet Jirou first.
You will find him at the northern-most waypoint, near the portal which leads to the perpetual machine boss.
He is at the top of the hill, stuck in a cage.
You need to get the cage key which is stuck on a tree (image below). It’s the second tree from the cage.
Unlock the cage and he’ll tell you about a treasure which requires the four old stone slates.
First old stone slate location
The first one is below the well, and you’ll reach the area if you have done A Strange Story in Konda.
Enter the well just like before.
Once you’re down here, get the electrogranum and enter the thunder barrier which leads to the shrine.
Look to the right of the shrine and you’ll see another barrier. Enter that barrier and climb up.
You will find the old stone slate near some crates as marked in the image below.
Second old stone slate
The second one is located northeast of Kamisato Estate, marked by the player location below.
You should see a few enemies in the area if you’re coming here for the first time.
The old stone slate is somewhere near the cooking pot.
Third old stone slate location
The third old stone slate can be found in Araumi where you did the cleansing ritual quest.
You basically have to jump into the broken tower at the huge tree. If you haven’t unlocked the area, you have to complete the electro statue puzzle.
Inside the dungeon, you’ll find an electro cube puzzle. You need to solve the puzzle by making them face the same direction.
After solving it, a precious chest will drop. You will notice that the water level below has dropped as well.
Jump into the water, turn left and swim all the way straight. You will see a some steps going up.
Go up the steps and you’ll find the old stone slate on a pile of dirt.
Fourth old stone slate location
The fourth stone slate is in the same area. You need to first lower the water level even further.
Do the five electro cube puzzle which is in the same room where you found the third slate. Make them face one direction and a precious chest will drop.
Now, go out of the iron gate. To the left, you’ll see a special gate that was previously blocked by water.
Go to the gate and start the console.
At the next area, you’ll find the underground waypoint in Araumi.
Also, glide down further to the broken boat / ship. There’s an old stone slate here.
The Farmer’s Treasure
Finally, you’ll unlock The Farmer’s Treasure quest.
Return to Saimon Jirou at the northern waypoint.
He’ll ask you to look for the treasure. Head to the location marked on the map.
This time, you need to dig up the soil to apparently find a fifth stone slate. There are four spots to dig.
After learning that it’s fake, go back to Saimon Jirou. You’ll see that he has ran away.
Head to the isle just beside and you’ll find Jirou there.
He will be in a cage again and there’ll be Kairagi there.
Talk to the leader.
The conversation will lead to a fight regardless.
You have to first beat the Kairagi and the Nobushi.
The next wave will be a group of Treasure Hoarders.
Lastly, you have to defeat a group of Fatui.
After beating all three types of enemies, you’ll be given the actual key. Open the iron gate.
Jump down and you’ll see a stone gate.
Place all four old slate stones on the ground.
Then, do the puzzle to open the stone gate. You just have to step all the tiles without overlapping.
Take all of the “treasure”.
Next, return to Saimon Katsumi in Konda Village.
The quest ends after the conversation. You’ll unlock the Saimon Heirloom Blade Diagram (Amenoma Kageuchi).