WBC No Shipping Math Trade
May 15, 2013

Math trades are a great way to swap games with other people. Eric Sokolowsky (esok127@gmail.com) will run a math trade at WBC 2013. The advantage of this math trade is there will be no need to ship any games saving time and a lot of money. However, you must attend the convention or give your games to someone that will be attending. NOTE: Trade matches will be complete before WBC Auction Store Preregistration ends in order to allow participants to sell games that do not trade.



  • Game submission begins June 8, 8 am.
  • Game submission ends July 6, 8 am. Want list submissions open at this time.
  • Want lists are due on July 13, 10 pm. Trade results will be posted shortly thereafter.

For those not familiar with math trades, an explanation of the process is below:


What is a math trade?

This is a trade between a whole bunch of people at once, using a computer program to decide who should give their game to whom. By matching together the likes and dislikes of a lot of people at the same time, many more trades become possible. Say Albert wants the game Power Grid, and Brian has a copy of it which they want to trade away. Brian doesn't want any of Albert's games, but would like a copy of Puerto Rico. Charles has Puerto Rico for trade, but doesn't want any of Brian's games. But Charles would like Alhambra, which Albert has and wants to trade away. So although there's no good trade between two of these people, the three together can each trade a game away to get a game they really want. The math trade software figures out these trade chains and assigns trades so that everyone gets games they want in return for trading away games they don't. In the above example you would have these trades:

  • Albert gives Alhambra to Charles and gets Power Grid from Brian.
  • Brian gives Power Grid to Albert and gets Puerto Rico from Charles.
  • Charles gives Puerto Rico to Brian and gets Alhambra from Albert.

How will this work?

In the first part of the math trade, everyone will decide which games they would like to trade away. These games are posted on a geeklist at boardgamegeek.com. Everyone will be able to watch that list as games are posted to see what might be traded. After a certain amount of time in this stage, the list is locked down preventing further changes for the second stage.

During the second stage, an online tool will allow each participant to select the games from a concise list that they are interested in receiving. Then the participant will be able to see a grid of checkboxes with their own games in columns and the games they are interested in receiving in rows. Then it is merely a matter of checking which specific games they would be willing to receive in exchange for each of their offerings. Only the boxes that are checked will be considered in the trade so there is no chance anyone would get something they did not select. The list of wanted games will be submitted to the moderator through an online tool call the On Line Want List Generator (OLWLG).

Sometime before the convention, the wants will be due and the trade will be run. Each participant will know well before the convention which games they will be trading away and which games they will be receiving. At the convention, all the participants will meet in the same room at the same time and swap games. The moderator will provide a place for the games each participant is receiving, so you just look for the card of the person receiving your games and drop them off there. Then when you have received all your games, you simply take them away and you are done! The whole exchange should last just a few minutes, as long as everyone is there.

It is important to note that these trades will be binding and if the participant cannot attend the convention and cannot find a proxy to take his or her place, he or she will be responsible for paying shipping both ways (both for the games being traded and the games being received). If a game cannot be traded at WBC for whatever reason, the best way to handle it is to submit an empty want list for that game.

As mentioned, the trade will take place through boardgamegeek.com. There are three lists on boardgamegeek for the trade. The first list is the discussion thread. You should read all of the rules in this thread and subscribe to the thread so you can be informed about any changes that may occur. You may also ask any questions about the trade here. The second list is the actual trade list. You will add a new item for each game you want to trade. You may list more than one game in the same geeklist item if you want to trade more than one game as a bundle (such as a game and its expansion). The third list can be used to post games you are interested in seeing in the trade. Potential traders can look at this list to see if they have something someone else wants, making trades more likely to happen.

Tips for new traders

  1. Follow the usual guidelines for trades and sales. Describe your game clearly. In particular, mention the condition of the game (especially completeness), the language of the game, and the edition (including publisher). It's in your interest to provide complete information about your game; others are more likely to want it.
  2. It can pay to check other traders' want lists. By offering a game lots of other people want, you greatly increase the chance you'll get something you want, too.
  3. If you're really hoping to get a particular game or games, try to offer a game of roughly the same or higher trade value.
  4. When offering multiple items together, try to group games that are related somehow. That way, you're more likely to find someone interested in the whole lot.
Boardgame Players Association Last updated by kae.
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