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The Science of BP Trading


We all know BP's will not come up as a full set and we will need to trade BP's 2 to 1 if we are to build that GB at that specific time. This article tries to discuss an approach on how to trade BP's. I also tried to add the reasoning behind any decisions. I hope this helps some players. Here we go:

1. Will you construct that GB now?

2. Do you have space to construct that GB now? If not, do you have the plan to create that space in your city (do not forget to consider the population and happiness)?

If any of your answers to these questions is no, do not trade your BPs now.

3. Do you have the goods to build that GB now? If not, do you have a plan to have them right after finding the last BP?

If your answer is no and you do not have a confirmation that you'll have the goods, then do not trade.

Reason: We are not trading under these circumstances because while we are waiting, we may be finding the missing BP. We have to save our BPs for unlocking the 11th and following levels, if possible.

4. Is your excess number of BP's at least twice of the number of missing BPs (ie. if your number of BPs are 3, 3, 0 / 1, 0, 0 / 2, 1, 1 then you have 5 excess BPs and 3 missing BPs. Even if you are lucky with your trades and find the missing ones in first 2 trades, you'll not be able to find the last BP)?

If no, as explained in Reason above, wait…

5. Always trade the two BPs you have most. If you have 2's and 3's and a 4, trade 4 and one of the 3's. Reason of this is same, spare separate BP's for the next unlocking, if possible. Never trade selecting only 1 BP. This will decrease your chance to find the missing one to 1/8 instead of 1/7 when you have 2 BP's selected.

6. If your trade is successful and brought you a/the missing BP congrats, you can happily construct or go to step 5 to find the next one.

7. If trade did not bring you the missing BP then go to step 4.

That's it. :)

Once you have your GB constructed and BP's keep coming into your inventory, you can unlock the other levels when they become a complete set. Do not trade your valuable BP's to unlock the next level of that GB if you have not completed building all of the current available levels. If you maxed out, then please go to level 4.



The other factor to consider is the likelihood that you will need to open up slots 11 and above on your GB. The Alcatraz and Arc are the two buildings most likely to be built beyond level 10. Trading 2:1 to get that final bp to build the GB may result in a longer time required to get all the BPs to open up level 11, and you might get stuck on level 10 waiting for more BPs. The other option is to save up 200 diamonds to buy that last BP, assuming you're ready to build.


Yep. However there are some GBs one is unlikely to need to unlock beyond level 10. For these, I don't have a problem trading in BPs to get that last BP once you have everything else needed to build it. If you're in the game for the long haul, for the Alcatraz and Arc, I would advise against trading in BPs, even if you have everything else.


The other problem is that when you only have 1 BP missing, there's only a 1/9 chance of getting the BP you are looking for when trading 2:1. You might get lucky and get it on your first trade, but then again....


Thanks 123. Subsequent to my post I read somewhere that you don't get a copy of the BPs you're trading in, in which case it's best not to trade in 2 of the same or else the odds would be 1 in 8


Thanks 123. Subsequent to my post I read somewhere that you don't get a copy of the BPs you're trading in, in which case it's best not to trade in 2 of the same or else the odds would be 1 in 8
You can't select two the same


good to see your return Gurkan, yes I can read m8, and I saw your point 5 but was looking for the explanation why the odds would be 1/8 or 1/7, instead of 1/9. I subsequently read elsewhere in the forum that earlier in the history of the game, you could end up with a copy of a BP you were trading in. Players complained about this, so inno changed the rules so that you would not get a copy of any of the BPs you're trading in, which improves your odds.


You can't select two the same
Yes you can- if you have at least 3 bps on one slot.

Have you read the thread thoroughly?
You are wrong and you are not understanding what you read.
What is your problem with reading???
3 of 4 posts you insult Angel, to no end whatsoever. You seem totally on the defensive about some silly gameplay element THAT HE ISN'T EVEN DISAGREEING WITH! I would ask you to please have some patience and refrain from insults, they serve no purpose at all in this thread...


OP's 1st post is in general good advice and new players would do well to read it and understand the logic and ignore the points scoring after the first post.


I agree HRC that this could have been a fascinating discussion with an opportunity to elaborate and clarify points and opinions. Unfortunately players who wish to seek clarification or are interested in adding their opinion may feel less likely to do so given the prickly nature of responses. Thank you for your support General Life :)
FWIW, my opinion is still that I would try to avoid trading in BPs for the Arc and Alcatraz if you are intending to get them well above level 12 quickly, because otherwise you run the risk of needing to hunt BPs when you are otherwise all set to level up again. If you are completing level 3 of GE you should be able to accrue enough diamonds to pay for that last missing BP, which is the hardest to get. It's not uncommon for long term players to get their Traz and Arc to levels 20 and above, so the need to keep collecting BPs continues long after the GB is built. Any trading has the potential to slow this process down, as you are losing 2 BPs to gain 1, resulting in a net loss of 1 BP with every trade, and only a 1/7 or 1/8 chance of getting the missing BP if there's only 1 that you need. The speed of accruing BPs depends on how available BPs are in your neck of the woods, eg. are there plenty of higher era players in your guild, neighbourhood and friends list where there is a reasonably chance of slowly accruing Arc or Traz Bps assuming you are aiding diligently, or are there plenty of Arc owners with whom you can engage in fp swaps for BPs?


Simple summary of BP trading:
1. Trade?
Yes, if you need the full set urgently and it's possible to finish the set with your existing duplicates.

No, otherwise.

2. How to trade:
Always trade 2 different BPs. Preferably the two you have the most of.