Failstacking with armor

A popular strategy used by players enhancing endgame gear is deliberately downgrading armor to build stacks for more important components, such as weapons. Today we will examine the soundness of this strategy from a financial point of view.

We will only examine downgrading DUO and TRI fodder tier armor today. In other words, the mathematics will be done with Heve/Grunil equivalent armor at DUO/TRI.

The concept of what we’re doing here is best illustrated with a tree diagram. Tree diagrams allow us to examine possible outcomes based on the odds, and make inferences based on them.


In mathematical terms:

  • The failstack cost analysis for armor enhance can be calculated as
    • ( CostArmorFail + CostEnhanceAttempt) * FailChance + (CostXFailstack + CostEnhanceAttempt – ExtraArmorValue) * SuccessChance
    • That equation calculates the expected outcome per action, but of course to reach your failstack goal you need to retry the outcome multiple times until you fail the enhancement.
    • The entire thing has to be divided by the probability of enhancement fail to give you the final equation:
      • ((CostArmorFail + CostEnhanceAttempt) * FailChance + (CostXFailstack + CostEnhanceAttempt – ExtraArmorValue) * SuccessChance) / FailChance
  • The failstack cost analysis for blackstone fodder can be calculated as
    • (CostXFailstacks + AverageStonesLost) * SuccessChance + AverageStonesLost * FailChance
    • That equation calculates the expected outcome per action, but of course to reach your failstack goal you need to retry the outcome multiple times until you fail the enhancement.
    • The entire thing has to be divided by the probability of enhancement fail to give you the final equation:
      • ((CostXFailstacks + AverageStonesLost) * SuccessChance + AverageStonesLost * FailChance) / FailChance


Next we need to figure out the multiple variables we need to complete the equations. We will examine this at 30 and 40 failstacks using DUO/TRI armor for the first strategy.

The cost of 30 failstacks and 40 failstacks can be worked out using combinatorics. This is too complex to summarize in this article, so I’ll just write the answers instead.

  • 30 Failstacks – 274.5 blackstones with Reblath+14
    • At 250k per stone and repair, this comes out to 68.6mil
  • 40 Failstacks – 1417.5 blackstones with Reblath+14
    • At 250k per stone and repair, this comes out to 354mil

The cost of DUO/TRI/TET Grunil as dictated by the market is:

  • PRI->DUO – 40m
  • DUO->TRI – 80m
  • TRI->TET – 120m

Using this and the KR enhancement table, it is now possible to work out all 8 scenarios and the cost of building additional failstacks using these.

DUO Grunil 30 stacks

((40 + 4) * 0.8 + (68.6 + 4 – 80) * 0.2) / 0.8 = 42.15m for 4 more stacks

TRI Grunil 30 stacks

((80 + 4) * 0.905 + (68.6 + 4 – 120) * 0.095) / 0.905 = 79m for 5 more stacks

DUO Grunil 40 stacks

((40 + 4) * 0.75 + (354 + 4 – 80) * 0.25) / 0.75 = 136.67m for 4 more stacks

TRI Grunil 40 stacks

((80 + 4) * 0.88 + (354 + 4 – 120) * 0.12) / 0.88 = 116.5m for 5 more stacks


And of course the cost using Reblath method.

  • Average stones used for 4 stacks = 1 + 0.85 + 0.85^2 + 0.85^3 = 3.19
  • Average stones used for 5 stacks = 1 + 0.85 + 0.85^2 + 0.85^3 + 0.85^4 = 3.71

How the above is derived can be found in an earlier article:

Reblath 30 stacks -> 34

((68.6 + 3.19 * 0.25) * (1-0.85^4) + 3.19 * 0.25 * 0.85^4) / 0.85^4 = 64.3m for 4 more stacks

Reblath 30 stacks -> 35

((68.6 + 3.71 * 0.25) * (1-0.85^5) + 3.71 * 0.25 * 0.85^5) / 0.85^5 = 88.1m for 5 more stacks

Reblath 40 stacks -> 44

((354+ 3.19 * 0.25) * (1-0.85^4) + 3.19 * 0.25 * 0.85^4) / 0.85^4 = 325.7m for 4 more stacks

Reblath 40 stacks -> 45

((354+ 3.71 * 0.25) * (1-0.85^5) + 3.71 * 0.25 * 0.85^5) / 0.85^5 = 445.9m for 5 more stacks


The numbers are self-explanatory. The values used in the market prices of various Grunil pieces are before tax, so they slightly understate the cost of building stacks using the high enhance armor fail method.

Because of how simple these equations are, I’m not going to elaborate on these findings in more detail. Feel free to play around with them by substituting different armor costs and come up with your own conclusions.

Additional thoughts:

Given these numbers, it’s pretty obvious anyone with their hands on the enhancement equations can easily manipulate this mechanic with Value Pack. This is also a proof of concept on how to directly accumulate a Valk’s Cry effect on your enhancement through buying and selling gear with Value Pack. In order to prevent the market from being ruined more than it is already, I have no intention of releasing the specifics of this strategy at this point in time.

Revisiting Liverto vs Yuria

Two primary concerns brought up for the previous article was the cost of materials and the value of Yuria as a cheaper substitute. Let’s examine those two propositions in this short blog post.

Liverto – Material Cost

I redid the maths on Liverto with 1.2m repairs (480k memory fragments), 300k armor blackstone, 300k weapon blackstone. As you can see, these new numbers are extremely unrealistic and biased. Not only can I list memory fragments in the market and make more than 480k even with the 35% cut, but why is memory fragment far lower than market value when blackstone isn’t, yet most people are actually bottlenecked by memory fragments?

I don’t know the answer to that question, all I know is some people think this is a good idea. To them, if you farm both memory fragments and blackstones with relic scrolls, memory fragments are cheaper but the stones aren’t. #logic?

Regardless here they are:

  1. +7->+8 force
  2. +8->+9 3 stacks
  3. +9->+10 3 stacks
  4. +10->+11 4 stacks
  5. +11->+12 4 stacks
  6. +12->+13 5 stacks
  7. +13->+14 7 stacks
  8. +14->+15 9 stacks

I strongly recommend not following the above values because obviously they underestimate the cost of memory fragments significantly. However, it is your decision.

If you’re a more reasonable person but still think the memory fragments are overpriced, at 1.8m repairs and 300k stones, take the failstacks in the guide and subtract each one by 2.

Liverto vs Yuria

If you still believe at equal enhancement Yuria is better than Liverto, you are in denial. However the assertion that Yuria is cheaper to enhance hence better is one worth investigating.

Here are the PRI, DUO, TRI, TET cost for Yuria and Liverto using the optimal strategy, 10mil sharp fragments, 300k weapon blackstone, 300k armor blackstone and 3.5mil repair Liverto, 200k repair Yuria. Increased gain of failstacks on fail, delevel, etc, are all accounted for.


  1. PRI: 37.5mil
  2. DUO: 60.5mil
  3. TRI: 306mil
  4. TET: 1.9bil


  1. PRI: 32.5mil
  2. DUO: 50mil
  3. TRI: 257mil
  4. TET: 1.6bil

As you can see, the cost of PRI->PEN weapon enhancement is predominantly gated by the sharp crystal cost. This is pretty obvious because it dwarfs the repair cost regardless of what weapon you choose to enhance.

What does this mean?

  1. We already know Yuria is weaker than Liverto at the same enhancement level. Slightly higher raw damage on human targets, but much lower accuracy.
  2. We now know that enhancing Yuria is also incredibly expensive, this means the whole “I can upgrade a TET Yuria instead of a DUO/TRI Liverto” argument is false.

The above two inferences direct prove that Yuria is terrible even for the purposes of conserving money and resources. If this doesn’t seal the debate for you, I’m afraid nothing will change your mind.


Hopefully this clears up a few queries about the Liverto upgrade guide. Due to the sheer stupidity of some of the comments I’ve been seeing, I will very likely no longer be responding to reddit threads. To reach me, you can contact me through PM.

Your New Liverto – A Daunting Experience

When a new player starts the game, I always tell them to skip Yuria and go straight to Liverto. The reason for this is simple, Liverto gives 15% more accuracy than Yuria, making it comparable to +15 Yuria when it’s only +12 or so. The cost of getting Liverto +11~+13 is lower than the cost of getting +15 Ultimate Yuria, yet functions identically and have longevity.

To me, investing in a Yuria is immediately setting yourself back 25million silver, because you quickly replace it with a Liverto, which is now easily accessible. A new player could simply cash in their free leveling gold bars for a shiny Liverto, and never have to worry about changing their weapon months or even years down the track.

[Edit] If you’re level 45 and you need a weapon ASAP, you can borrow a Kaia weapon from Kanobas in Calpheon for 50 contribution points. This weapon can be used while you get your Liverto to an acceptable enhancement level. Credits to jimcdiver on BDO Discord for bringing this to my attention.

If this is your experience, you’re in luck. This blog post will teach you how to get to +15 Liverto in the cheapest way possible. Note: as with all RNG, this is subject to fluctuation. The strategy here maximizes your odds, but does not guarantee them.

In order to work out the optimal strategy, you need to know:

  1. The amount of tries on average. I covered that topic here previously.
  2. The cost of each enhance attempt, blackstone + memory fragments. Straightforward.
  3. The cost of building X number of failstacks. I will cover this topic eventually.

For every value of failstack, the price of the enhancement can be calculated by:


To save everyone the trouble of doing thousands of rows on Excel, I did this for you already.



Focus only on the blue cells. Some of the rest do not apply to enhancements before +16. The costs used in this spreadsheet:

  1. Memory Fragment: 800k each.
  2. Blackstone (Weapon): 300k each.
  3. Blackstone (Armor): 200k each.

How to build failstacks:

  1. Make a level 10 alt. Kill 1-2 horses so your karma is negative.
  2. Enhance Reblath pieces until desired failstacks reached. Reblath can be purchased from the Velia Blacksmith.
  3. If your Reblath hits +15 at any point, equip it on your negative karma alt and suicide in PvE a few times until it delevels back to +14.
  4. Continue to build stacks on your +14 Reblath until desired stacks reached.

[Edit] If you still have armor pieces not +15 yet, you should build failstacks on those instead of buying a Reblath. Thanks to reddit user asdf2100asd for bringing this to my attention.

And here is the optimal strategy.

  1. Buy Liverto+15 premade if it’s on the market and you can afford it. If not, follow step 2 to 10.
  2. Enhance your Liverto to +7. This has a 100% success chance.
  3. Force enhance your Liverto to +8.
  4. Build 7 failstacks and attempt to upgrade your Liverto to +9. This will cost you 6.3mil on average.
  5. Build 8 failstacks and attempt to upgrade your Liverto to +10. This will cost you 7.7mil on average.
  6. Build 9 failstacks and attempt to upgrade your Liverto to +11. This will cost you 9mil on average.
  7. Build 9 failstacks and attempt to upgrade your Liverto to +12. This will cost you 12.3mil on average.
  8. Build 10 failstacks and attempt to upgrade your Liverto to +13. This will cost you 14.8mil on average.
  9. Build 12 failstacks and attempt to upgrade your Liverto to +14. This will cost you 18.7mil on average.
  10. Build 13 failstacks and attempt to upgrade your Liverto to +15. This will cost you 21.8mil on average.

I listed the prices above so you can have realistic expectations about how far you go. You could be luckier, you could be cursed. To those who are slightly more maths savvy, the numbers quoted are means. Because the distribution of enhancement is right skewed, more than half the players who attempt this will be able to do it with cheaper than the stated prices (median).

That’s all for today. Remember:

  1. Yuria is meme. Never use that junk.
  2. Enhancement is all about maths. Delete “it’s all RNG” from your vocabulary. Your IQ will go up 20 points instantaneously, trust me.

[Edit] Response to some queries. 

Demythifying Failstacks

Failstacks is a hot subject for discussion with the release of +16 to +20 enhancements. Many consider it essential to build as many failstacks as possible and that doing so would guarantee (or significantly improve the odds) of successful enhancement.

Before we continue with the discussion about failstacks, all of the numbers in this post assumes the KR enhancement table is correct, i.e.


For example, reading the 16 row we can see that an enhancement from +15 to +16 would go from 15% success chance up to 52.5% at 25 failstacks. This may seem like a significant boost of over three times, but how much does that translate into real value?

We know that on average it will take you (1/0.525) = 1.9 tries to enhance a piece of +15 gear to +16 starting from 25 failstacks. However, if you subsequently assume that it takes you (1/0.15) = 6.67 tries to enhance a piece of gear starting at zero failstacks, you would be wrong. The reason is because with each fail, you will build failstacks, and for weapon and armor, +15 to +16 builds 2 failstacks.

The expected number of tries can easily be mapped out with an equation, but instead of confusing everyone I will instead rely on an analogy to explain.

Say 1000 people are flipping a coin, and once you flip heads (success) you don’t have to flip anymore. When every single person is finished flipping, how many flips did each person do on average?

After the first flip, 500 people would have flipped heads on a fair coin. On the second flip, half of the remainder will have flipped a heads. On the third flip, half of the remainder would have flipped heads. On a practical level, we know each of the 1000 will finish flipping, but on a mathematical level, we know that there is a small chance that someone might spend the rest of their lives flipping coins.

The answer to the above question is very simple, 1000 people will flip once, 500 will flip a second time, 250 flip a third….. infinite. Therefore the answer is simply 1000+500+250+125+62.5…… divided by 1000 people. On average, each person will flip the coin twice.

Some of you might have figured out that this question could have been more easily solved by simply dividing 1 by 50% chance of heads, which is true, however that only works if the probability of tossing a heads does not change. It doesn’t change for a fair coin, but BDO enhancing is not a fair coin. Each time you fail, the probability of success goes up because of failstacks.

This method however can be applied when calculating failstacks. We simply need to add the probability of succeeding, the probability of fail->success, the probability of fail->fail->success….. infinite and we will get the expected number of tries on an enhancement.

To save everyone the headache of filtering through a huge list of equations and numbers, I did that for you all on Excel. Yes, I did account for fails giving 4 stacks instead of 1 stack. Here is the average amount of attempts required to successfully enhance a piece of gear from +17 to +18:

17 to 18 stack

Note the above does not take into account the number of tries leveling a +16 piece of gear back to +17 thanks to deleveling. It strictly only measures the amount of times you will put a +17 piece of gear and a concentrated blackstone into the menu and have the Black Spirit laugh at you.

As you can see, if you start from zero failstacks, it will take you 7.4 tries to succeed on average. Doing it at capped 44 stacks drops this to 3.7 tries but 44 failstacks is semi-impossible to build on purpose. Doing it on a modest stack like 25 drops the attempts to 4.5 tries.

It’s always kind of funny watching people on the forums complain about failing +18 three times. The average player is expected to fail 3.7 times even if they start at max stacks.

The above really goes and illustrates a few very important concepts:

  1. Failstacks does not guarantee success. You need to try many times regardless of how many failstacks you build.
  2. Valk Blessing that many people are begging to have implemented into our version actually does almost nothing. Going from 34 stacks to 44 stacks drops the amount of tries on average by 0.3 tries. This is negligible.
  3. It is not always the optimal strategy to build maximum failstacks. Building 40 failstacks costs an astronomical value compared to say 20 failstacks, but only drops your expected tries by a bit over 1 try.

Optimal stacking breakpoints is another monster in itself and maybe we’ll talk about that another day. Hopefully this post is able to provide some insight into BDO failstack system and dispel the myth that there is a huge effect on success at modest values.

If you have any suggestions about this post or on topics to cover, feel free to contact me or leave a message below.