Gaelcon Boardgame Math Trade

Gaelcon Boardgame Math Trade


There will be a boardgame math trade at this year’s Gaelcon! A math trade is a great way to trade some of the games which you haven’t played in ages for other games that you are interested in. The trade itself is hosted on Boardgamegeek here. This does mean that you must be a registered member of the Boardgamegeek community to take part but registration is a quick and simple process. The deadline for submissions is the 19th of October.


In a math trade participants first post the board games they are interested in trading to the trade Geeklist. They can do so by clicking the ‘Add Item’ button on the top post of the Geeklist. After the submissions deadline a post will be made by the organiser which gives each of the submitted games a unique code. For example


001soc Settlers of Catan

002sld Splendor

003kot King of Toyko


All participants then submit which games they would be happy to trade their games for. This is submitted to the organiser in the format of


(MyUserName) MyIDName : IDName1 IDName2 IDName3 IDName4


Where ‘MyUserName’ is your Boardgamegeek username (in brackets), ‘MyIDName’ is the list id of the game you are trading and everything after the colon is the list of games you would take for that game in order of preference. For example, if Eoin had submitted Settlers of Catan as a game he would like to trade during the submissions period he would then submit something like the following


(Eoin) 001soc : 003kot 002sld


This signifies that Eoin’s preference would be to receive King of Toyko for his copy of Settler’s of Catan but he would also accept Splendor.


Once all participants have submitted their Want’s List a computer algorithm will determine which trades will occur. It does so by calculating the trades which will maximise the ‘happiness’ of all participants based on their submitted Want’s List. This algorithm is the reason trades like this one are called Math trades. The end result will look something like the diagram at the top of this page.

The algorithm has found that to maximum the happiness of all participants Eoin should trade his copy of Settlers of Catan to Fergal. Fergal will then give his copy of Splendor to Anna who will give her copy of King of Tokyo to Eoin.


When submitting your boardgames to this trade you may request that trades only occur at Gaelcon. The deadline for submissions is the 19th of October and the deadline for your Want’s List is 25th of October. Much more information can be found on


This is a great way to reinvigorate your boardgame collection for free! See you all at Gaelcon!