You're not allowed to build the same building more than once. I noticed that this rule is easily overlooked, especially in 7-player games and when the table is not that big (and so the cards need to be partly stacked).

If a player has built a building twice, but it is only spotted in the following round(s), what can you do?

  • Discard the card
  • Discard the card and give the builder 3 gold
  • Let the builder choose: discard card for 3 gold OR use the card to build the wonder
  • Keep the building
  • … something else?

Of course there might be other side effects, as when the builder (or neighbours) already made use of the illegal building. It could be very hard to retrace everything, so I guess it'd be best not to try to undo any side effects.

  • This can happen in Castles of Burgundy as well. There doesn't seem to be a clear-cut answer to the CoB situation, as some buildings have immediate, "Extra action"-esque effects, while other building have game end bonuses. Dec 1, 2012 at 17:30
  • Related: thread on boardgamegeek.com
    – unor
    Dec 1, 2012 at 21:12
  • 1
    As a tip, we ask that players watch their military neighbors (immediate left and right) play their cards, and double check their resources and existing buildings to keep some semblance of checks and balances in place. Or have a ref.
    – yurisich
    Jan 11, 2013 at 22:02

3 Answers 3


If it is too late to undo, option 3 is your best bet (assuming they can build their wonder). If it's been more than 2-3 turns, and other people have been using their resources, I might consider letting it stand. Especially true if there are a lot of people who haven't played before in the game.

Really it's not the end of the world, unless a player consistently does it (e.g. more than twice) in which case it's probably cheating.

  • 5
    +1 for explicitly mentioning that it is not that bad, if it just happens sometimes. Indeed I would recommend to keep it - after all, all other players didn't notice it either. It has been proven useful in our group btw. to announce which buildings built, which gives a better overview to all players.
    – mthomas
    Dec 1, 2012 at 23:50

Our group's practice has been to discard the extra building and treat it as if the player discarded the card for 3 gold. 7 Wonders is a fast game that I try to keep the game moving at a brisk pace, and the 3-gold discard eliminates the extra decisions (should I build a Wonder stage, can I afford to, which neighbor should I pay, wait did my neighbor even have the resources I needed to buy all those turns ago) that would otherwise keep the game waiting.

It's relatively rare that there are important side effects that need to be undone (rarely do you need to buy more than one of a resource from a single opponent) but it should be straightforward to reverse a military victory/defeat if there's been an age ending in between.


Since this happens most often with science buildings, which means you won't really have gained any new capabilities with them, we just have the player discard for 3 gold and move on. The other one that it seems to happen with is basic brown cards, which may have enabled the player to build something they shouldn't have been able to build. If we can identify any of those buildings, they'll have to hand over payment to a neighbor as well. That's all the unwinding we've ever done, really.

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