The Valley Engraving Permit is a late-game currency item in Arknights: Endfield that transforms essence farming from pure randomness into controlled optimization. When used before a Severe Energy Alluvium run in Valley IV, it lets you lock in one specific secondary stat or skill attribute on the essences you receive, eliminating the frustration of farming dozens of times only to get unwanted rolls.
Quick answer: Use the permit at Severe Energy Alluvium sites in Valley IV to guarantee one secondary or skill stat on your essence drops. Each permit costs 400,000 to 800,000 Valley Stock Bills and is consumed per run.
How to unlock and purchase the permit
The permit becomes available only after you unlock Valley IV and upgrade your Stock Redistribution Terminals. Valley has three separate terminals, each with four upgrade levels that stack together. You must fully upgrade these terminals to unlock the permit in the shop inventory. Once available, the permit rotates in and out of stock, so check back regularly—some instances appear at a discount (400,000 bills instead of the standard 800,000).
Purchase the permit from the Valley IV Stock Redistribution Terminal using Valley Stock Bills. If you see a discounted version, buy it immediately, as there is no cheaper or faster way to obtain it.
Using the permit during Severe Energy Alluvium runs
Before you start a Severe Energy Alluvium challenge at the Originium Science Park in Valley IV, a new menu option appears: "Current Pre-Engrave Stats." Select this option to open the engraving interface. You will see a list of available secondary stats and skill attributes. Choose exactly one stat you want to guarantee on the essences you earn from that run.
Once you confirm your choice, the permit is consumed, and the run begins. Any essences you obtain will have that stat pre-engraved, eliminating randomness for that attribute. You cannot use the permit without it in your inventory, and attempting to start a run without one will prompt you to either proceed without engraving (resulting in fully random rolls) or cancel.
Strategic stat selection
Choosing the right stat depends on your operator and weapon type. Skill-focused characters benefit from Ultimate Gain Boost, Efficacy, or Inspiring stats to speed up ability cycles or amplify team value. Elemental damage builds should prioritize the corresponding damage boost: Electric DMG Boost for electric weapons, Cryo DMG Boost for cryo, Nature DMG Boost for nature, or Arts DMG Boost for arts-based builds.
The permit's true power emerges when paired with Sanity Usage Permits. Using both together lets you run the same Alluvium twice in one session, effectively doubling your chances at near-perfect stat rolls on already pre-engraved essences. This combination defines Endfield's endgame farming loop.
When to use permits
Save permits for operators at level 60 or higher when you are farming Flawless Essences for final build optimization. Using them early on lower-level characters wastes their value since you will replace those essences as you progress. Once your core team is geared, permits become essential for min-maxing secondary stats on weapons you plan to use long-term.
Without a permit, essence farming is pure chance—you spend Sanity hoping random rolls align with your build. With a permit, you shape the outcome directly. This shift from gambling to planning marks the transition from leveling gameplay to true build crafting in Valley IV.
Stockpiling strategy
Many players maintain a stockpile of 20 permits as a buffer. Since natural weekly Sanity recovery only funds about 21 runs per week (or 24.5 with a monthly pass), you do not accumulate permits faster than you use them during active farming. Buying permits now and holding them ensures you have supply when you unlock new weapons or decide to optimize additional characters later.
