Arknights PSA: Event Supplies And Potions - Is It Really Better to Farm 1-7?

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Article by Daniel O'Brien

Probable Probability

Update 7/3

After further research and analysis from posts here and here, we have drawn the following conclusions:

  • It is almost certain that lucky drop rates are based on sanity cost and not equal per-stage.
  • Analysis of CN drop rates determined that farming 1-7 was about 5% more sanity efficient than higher sanity cost stages, though the sample size for higher sanity cost stages is not very large.


  • If you really want to make sure you don't miss out on any potential sanity efficiency, or don't have anything specific to farm, then farm 1-7, you've got nothing to lose.
  • If you want to farm other things, at worst the potential sanity loss is small.

------ Start of Original Article ---------

As all of you likely know by now, the launch of Episode 6, Partial Necrosis, has brought along with it a "Lucky Drop" campaign.  During this time, each stage has a chance to drop Rhodes Island Supplies (which has a chance to provide enhancement materials) and/or Emergency Sanity Sampler (restores Sanity).  More details about these items (including contents) can be found on their wiki pages here:

The question I currently see being debated is the following:

  • Is the drop probability of these items the same for completing all Stages, or is it based on Sanity spent?

Based on the results of my research so far, the answer is: We don't know.

Here is what we know:

  • According to CN sources, the first time this campaign was run, the drop probability was the same for all stages.  In subsequent runs it was changed to be based on Sanity used for the stage.  For the global run, we don't know if it is the same as the first CN run or the later ones.
  • In the in-game english descriptions for drop probability, lower Sanity cost Stages (like 1-7) show the probability of getting the extra drops as "Very Rare".  Higher Sanity cost Stages (like 5-10) show the probability of getting the extra drops as "Rare".  This seems to imply that higher Sanity cost Stages have a higher chance to drop the special items than lower sanity cost stages.  Examples can be seen here:
Stage Rewards for 1-7
Stage Rewards for 5-10
  • We do not have any statistically significant drop data for Global, as far as I know, so there is no way to know currently which is the case.

Why does this matter?

If the drop rate is equal per stage clear, then it obviously follows that, because of the extra possible rewards, it would be more sanity efficient to clear lower Sanity Cost Stages, like 1-7.  If the drop rate is based on Sanity spent, then it really doesn't matter which stages you clear, they should all be more-or-less equally efficient as far as the Campaign drops go.

What is the TLDR Dammit!?

  • We don't actually know if the event item drops are based on Sanity spent or the same for all stage clears, so you might not be getting extra efficiency from spending all your sanity on 1-7.

If you happen to have more detail or data on this subject, please let me know in the comments below or via Discord or email so I can share it with the community.  Cheers!

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About the Author(s)

Arknights: Alyeska#2654

Discord: Alyeska#7717

Wanderer, Gamer, Eternal Student, and Weeb.

Lover of Language, Learning, Unique Humans, and Community.