Six Cipher Letters can be found in the Fontaine Research Institute area of Genshin Impact's 4.1 update. Check out all the Cipher Letters' locations, the rewards and achievements obtained, and how to decipher them in this guide!

Cipher Letters Locations

Overworld Map Locations

Cipher Letters Locations
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Cipher Letter 1	Cipher Letter 2	Cipher Letter 3
Cipher Letter 4	Cipher Letter 5	Cipher Letter 6

Individual Locations

Cipher Letter 1

The area can only be accessed while doing the Fontaine Research Institute Chronicles World Quest. Activate the Energy Transfer Terminal and you will see the Cipher Letter between a window and a bookshelf.

Cipher Letter 2

Teleport to the nearby Waypoint and head down to the floor below, there will be a Viewfinder puzzle. You don't need to do the puzzle to view the Cipher. Interact with the Energy Transfer Terminal and you will see the CIpher on a wall left of an energy storage device.

Cipher Letter 3

From the Teleport Waypoint, head towards the Experimental Field Generator boss. Go to the second floor of the ruins and you will see the Energy Transfer Terminal. Interact with it and the Cipher will be in front of the Viewfinder.

Cipher Letter 4

Glide down from the nearby Teleport Waypoint into the basement of the ruins. There will be a lengthy Pneumosia and energy storage puzzle to access the Energy Transfer Terminal.

The Terminal to view the Cipher will be behind a gate. Interact with it and switch your viewfinder with the one in front of you. The cipher will be on a wall next to the viewfinder and a Chandelier.
Institute Dormitories Puzzle Guide

Cipher Letter 5

The Energy Transfer Terminal is located above the ruins guarded by two Mekas. Defeat them to unlock the terminal and point the viewfinder to the Cipher above a bookshelf. You can also solve the Pneumosia puzzle.

Cipher Letter 6

Teleport to the nearby Statue of the Seven and head down the nearest stairs. Turn left, and you will see the Energy Transfer Terminal. Activate it and switch to the viewpoint in front of you. You will see the cipher right next to the viewpoint.

Cipher Letters Rewards

Recieve an Achievement

The Calendar of the Future Is Longer Than the Diary of the Past Achievement

You can recieve an achievement once you decipher all 6 Ciphers located around the Fontaine Research Institute. You can obtain 5 Primogems from doing so.

How to Decipher the Cipher Letters

Use Energy Transfer Terminals to Access Terminal Viewfinders

The Cipher Letters can be deciphered if you use the Energy Transfer Terminals to connect to the Terminal Viewfinders. Just point the Viewfinder to the cipher and wait for the Viewfinder to decrypt the text.
How to Use Energy Transfer Terminals

Cipher Letters Information

Related Quests

Collect While Doing the Fontaine Research Institute Chronicles World Quest

To unlock Cipher Letter 1, it is required to do the Fontaine Research Institute Chronicles World Quest. You are required to go to every area where the Ciphers are located at while doing the quest.
Fontaine Research Institute Chronicles Guide

What are the Cipher Letters

Probably Left by the Inventor of the Experimental Field Generator

The Ciphers are likely left by the creator of the new Boss, the Experimental Field Generator. The writer talks about wanting to best Maillardet, the researcher on the Icewind Suite, at making a better Meka.

The Ciphers also talk about the use of Plaustrite, an ore found in Liyue which makes Xiao Lanterns float. This is probably the reason why the boss has an affinity for Geo and has control over gravity.

Experimental Field Generator Boss Guide

Genshin Impact Related Guides

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All Tips & Tricks Guides

All Version 4.1 Tips & Tricks

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