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On-Line Want List Generator for Math Trades

If you are looking for my Geek Auction Gateway instead please click here.

Microbadge: Microbadge: Math Trader
Awards: OLWLG honored (indirectly) as BGG Geek of the Week

In addition to the following here are some other resources:
Asher's Updated math trade & duplicate protection video tutorials (OLWLG)
Jim Stevens Math Trade Video Tutorials
Rahdo's how to use OLWLG video
Steve's geeklist w/images on general use of the OLWLG
Chris's geeklist w/images on duplicate protection
Utiliser OLWLG A French translation of this guide
History of Math Trades on BoardGameGeek

The new (as of Jan 16, 2016) official place to ask questions, suggestions, etc as this is much preferred over geekmailing me, thanks!) is the BGG guild On-Line Want-List Generator (OLWLG), for Math Trades

If you are a math trade organizer also see OLWLG For Organizers

Table of Contents

The following is deliberately verbose. If you are the type like me who doesn't always read directions, you can try skipping to the heading "Location of tool"

What is this OLWLG?

OLWLG stands for "On-Line Want List Generator". It is a tool to help one compose their want lists when they are participating in a Math Trade

Step 1 (login)

First visit the OLWLG Website then...

Login to the tool using your BoardGameGeek username. This is a two part step. First you'll provide the tool your BoardGameGeek username. The tool will send you a geekmail (on BGG) with a link you'll need to use that will end up logging you into the tool.

Note: if you are restricting Internet cookies, you need to allow the cookie BGGID to be set. This is the only way the tool can remember who you are.

Note: BoardGameGeek needs to be up at the time, login requests aren't queued, and the OLWLG currently doesn't detect failure trying to send the geekmail. If you don't receive the geekmail and BGG is up and running, try the login link request again.

Step 2 (pick math trade)

After successfully logging in you are redirected to a page that welcomes you, and has a list of the current active math trades this tool is aware of (right now it's hardcoded).

Click on the appropriate math trade name

Step 3 (add items)

This is the table that lists all the items as of the last snapshot that are in the math trade.

Column one contains the current geeklist item number, the image which is hyperlinked to the open a new window to the actual item in the geeklist, an "Add" button (or a green image of a check mark if you've already added it).

The "Add" button (or green check mark) results in a sub-table being displayed at the bottom of the corresponding 2nd column. The sub-table lists the name of the main game of each of your own items in this math trade, and a checkbox before each one. Select (or un-select if clearing previously selected) which of your offerings you are willing to trade away for the given item.

Click on "save" to save the selections, or "cancel" to abort and no changes will be made. In both cases the sub-table should disappear. In the case of "save" the "Add" button should change to the green check mark image. If you clicked "save" and the sub-table does not disappear (give it a little time if it's not quick) an error may have occurred (the inlined frame at the very top of the page may have more information).

After you've added your 1st want, right before and right after the table should now be a link "Click here to edit your wants" which takes you to the next step (in a new window).

Hint: you can "Add", make no selections, then click "save" if you simply want to flag an item you may be interested in. You can either come back to it later to choose which of your items you are willing to trade for it, in either this step, or in the next step.

The entire table is sortable(*) by game name, rank, rating, bgg modfiied (bay) rating, and the person who created the geeklist item. To do so click on the table headers (click same header again to sort in reverse).

Note: the tool needs both JavaScript, CSS and IFrame's (inlined frames) enabled.

* = Note: the re-sort may be slow on some platforms/browsers

Adding Sweeteners

In your offering you can offer more than one game as part of the same item (bundle). You can add them using the "Insert Geek Item" pull down or using the [ gameid = nnnn ] format.

Note: if using Insert Geek Item... make sure the start tag and end tag are on the same line... such as:
[ thing = nnnn ] quick brown fox [ / thing ]

Step 4 (edit wants, dup protection, etc)

After you've added the items in Step 3 and then clicked on the "Click here to edit your wants" you are taken to another page where you can edit your wants some more in a different way. A matrix of checkboxes in table format is given where there is a column for each of the items you have in the math trade, and a row for each item you are interested in receiving.

This rows in this table are sorted 1st based on optional values you assigned (see Ordering section), then how many of your items you indicated you would trade for it, then on how many folks on BGG in general have it marked as "wanted" in their collection. In theory the most valuable (to you) items you want are listed higher up.

The columns are also sorted based on how many different items each of your items wants. In theory the most valuable (to you) of your items are listed closer to the left side of the table.

In this format, if it's anything like mine, you'll find the highest concentration of checked checkboxes grouped in the upper right hand corner of the table.

Click on "Confirm Changes" to commit any changes, or "Reset Changes" will reset the table to the way it was when the page was loaded.

Step 5 (submit want lists)

You can actually do this at any point during Step 4 but in theory this will be the last thing you do.

At the top and bottom of the page is a borderless table with different colored cell backgrounds. This is like a tab'ed page, you can click on each one to display your want lists in different formats.

  • Table (edit format)
the default format described above
  • Summary
html list format (looks similiar to what my want list verifier displays)
  • Duplicate Protection
see heading on this topic
  • Submit Your Lists Here!
self explanatory... only available during want list submission window
  • Official Format

what will go into TradeMaximizer... only available after math trade open to want list submissions

Note: if you made changes in "Table (edit format)" that you have ""not"" saved yet, they will ""not"" be reflected in the other formats (you have to go back to the table/edit format and save them).
This tool is unofficial and you should still check your lists against the official summary (if there is one).

Online submission via this tool is now supported... it does depend on the math trade and if the math trade organizer has authorized submission via this tool.

Note: with online (via OLWLG) submission you can submit and then re-submit as often as you want up until the organizer turns off online submissions with no extra work for the organizer.

This tool internally uses and stores the unique BGG geeklist item "identifiers" for each geeklist item. This means it should be unaffected by changes in the geeklist order (such as an item being deleted).

Location of tool

You can find the first (login) page to the tool at:

I know the information given above seems overwhelming and possibly complex. However I hopefully designed the user interfaces so that the use of the tool is relatively intuitive.

Color Coding of Items (step 3)

The OLWLG will color code items (and sweeteners) based on your BGG collection data (on each game page under the "User Information" heading you can click on "Record information" and check various boxes such as "want in trade", "owned", etc). The color coding used is displayed in step 3 (above the table of items).

In order to make sure the OLWLG has your updated collection data, on the OLWLG "home" page after the list of "Active Math Trade(s)" it tells you when your collection data was last resynced and there is a link you can click on to force the OLWLG to resync it.

Note that you can override the default colors by going to your OLWLG "profile" (link in navigation bar) and scroll down to "step 3 highlighting colors"... you can use any named colors your browser understands, see a table here, including using #hexnumber syntax. You also specify the foreground (text) color by using the syntax background/foreground such as yellow/blue.

Alternative Name for non-game items (altname)

The OLWLG will only look for an "alternative name" (altname) meta tag on the following game id's (and only on the geeklist item, sweeteners ignored):

5985 Miscellaneous Game Accessory
18291 Unpublished Prototype
18785 Miscellaneous Game Magazine
22104 Miscellaneous Game Merchandise
22427 Miscellaneous Game Book
23953 Outside the Scope of BGG
31693 Miscellaneous Miniatures Game Accessory
33456 Miscellaneous Card Game Accessory
94718 Memorabilia, Programs, Catalogs and Other Material
97962 Outside the Scope of VGG

Also a reminder that the opening and closing tag need to be on the same line, such as:

+altname+ $25 Walmart Gift Card -altname-

there should be no BGG markup (bolding, italics, etc) on the tag or in the short alternative name itself.

Also important.... the alternative name should be SHORT as possible... it's not only displayed in step 3 but also in step 4 for both you (vertically in a column header) but for everyone who may "add" your item, and trying to cram in a big description makes it more difficult for everyone. Folks can always see the full item description just like for any regular item.

Also remember that the altname tag and its contents are "consumed" by the OLWLG meaning that the OLWLG removes it from the description as it's being used for the name (title) instead.

Detecting geeklist Comments on Your Items

The OLWLG now detects (when a resync is being done) items for which the last comment is not by the item's owner. The assumption is that it's a comment someone has a question about the item, and the item's owner has not yet responded.

In step 3 when the item is being viewed a red background note is added at the bottom of the description and a link to the BGG item.

In addition in step 3 and 4, if any of your items have this type of comment (ie. last comment is not by you, the item's owner) a warning is given near the top of the page along with direct links to the geeklist items.

This should hopefully help avoid problems with comments not being seen by the item's owner (due to the lack of BGG support for the item's owner to be able subscribe to be notified when comments are added to their items).

ps: note that if you, as the item's owner, adds a new comment to the item, it won't be detected by the OLWLG until the next time the OLWLG resyncs with the geeklist

%Options%/%End% block in item listings

An %Options% block in a listing can be used to have the OLWLG make multiple identical copies of your listing available. The block can also be used to tag the main item in the listing with a specific BGG version.

Note: the OLWLG will only find and use the 1st %Options% block in a listing, others in same listing will be ignored (so no current way to specify/tag the version on sweeteners in your listing).

If use OLWLG's "addmygames" feature it will automatically pick up the version data from your collection and will try to make sure both version and copies options are in a single %options% block.

How to Offer Multiple Identical Copies/Bundles

Some folks have more than one identical copy of the same item (tanga or other deals/sales). One could and still can add them all to the geeklist as individual items. The problem is that it not only makes it more work for you to manage (in the OLWLG it's more columns in step 4 and a bigger popup in step 3 and in both more checkboxes), but more work for everyone else as well (more items to skip over if they aren't interesting, more individual items and having to setup duplicate protection even if no one else is offering the same item).

Instead you could add a single geeklist item but in that item's description add...

Copies: 2

Where "2" can be the exact number you have. Then you and everyone else can treat it as a single item.

Note: this requires that the math trade organizer use the OLWLG for generating the official "summary" in the least. You yourself should also be using OLWLG to generate your want lists as your item will be expanded automatically into multiple want lists. Other users wanting your item and the OLWLG will get automatic duplicate protection for your item.

See here for more information on this functionality

How to specify the BGG version of your offered item

If you use the OLWLG "addmygames" feature and you have selected a version on your various BGG collection data then addmygames will use it. Note that it adds "VersionID:" and a human readable "Version:"... the latter is for those viewing the item on the BGG geeklist itself.

See here for more information on this functionality

Duplicate Protection (dummy/pseudo items)

This is perhaps the most confusing part of math trades and using it in the OLWLG.. however properly setting up duplicate protection ensures that you will not receive duplicate copies of the same games if you don't want to.

Instead of trying to describe it right now, for now I point you to...

Chris's geeklist w/images on duplicate protection

Warning! Non-empty Dummy Items Not Being Used

Warning! Non-empty Dummy Items Not Being Used
The dummy item(s) "TEST2" have non-empty want lists themselves, but are not wanted by any of your real items.

What this one means is that you have some dummy item(s) that have non-empty want lists themselves (if you look under the column for these dummy item(s) in the Table/edit format of step 4 there are box(es) checked)... but the dummy item(s) themselves are not wanted by your real items (if you look at the row for the dummy item in step 4 for the dummy item there are no box(es) checked).

Warning! Empty Dummy Items Being Used

Warning! Empty Dummy Items Being Used
The dummy item(s) "TEST" have empty want lists, but are wanted by your real items.

Essentially the reverse situation as the other warning above. The dummy items have empty want lists (no boxes checked in the column for the dummy item) but the dummy items themselves are wanted by your real items (in the row for the dummy item there are boxes checked).

Ordering Your Wants, Relationship to Priorities

In step 3 when you "add" an item there is an "Optional value" you can specify an integer value, and in step 4 under the 2nd (Game) column for each item there is a small unlabeled text box to assign/edit these values.

To be clear... they are not "priorites".... the are relative "values" which are only relevant to you and overriding the default OLWLG sorting. If the math trade were using priorities then priorities would be assigned based on both the type of priorities being used and the relative position of the wants on an item by item basis. The OLWLG doesn't deal with priorities, that's the job of the trade resolver (TradeMaximizer).

The sorting order from primary key downwards is:

  1. . your assigned "values" from highest to lowest, with items w/no values treated as if they had a value of 0 (negative values are allowed by the way)
  2. . number of boxes checked in the row for each item. in "general" this pushes up items you value more because you are willing to trade more of your items for a given wanted item. Obviously this works best for folks with more items in the math trade (and is worthless to someone w/only one item).
  3. . the number of all users on BGG (not just in the math trade) who have the item marked "want in trade"**
  4. . the number of all users on BGG (not just in the math trade) who have the item marked "wishlist"**

** = this value is from the game's page (via the bgg xml api) and is cached by the olwlg for this math trade (both for performance and so the values stay stable for the duration of the math trade). You can see both these values for each item in step 3

Ordering Your Own Items

These are ordered the same way as your wants... except you can't assign "values" yet.
Update: you can now assign values to your own items, see this thread.

"To Do" List

This list is now it's own wiki at "OLWLG bug and wish list"

Frequently Asked Questions

Never received geekmail for login or wants submission

If BGG is down or has a hiccup at the time you requested it then you'll never receive it. Simply retry when you know BGG is up.

Note that for wants submission (via OLWLG) as long as the OLWLG tells you it was successfully submitted then it was submitted even though it was unable to send the geekmail (the geekmail simply contains the same summary as you should have reviewed when you submitted).

How long does it take to see my items in the OLWLG?

New items added (as well as edits and added comments) to the geeklist will only show up in the OLWLG the next time the OLWLG resyncs with the geeklist. This is usually done manually by the math trade organizer.

Note that you can still "add" (step 3) items you may want and go back later to edit which of your items you would trade for each item you may want.

Where is the green "Submit Your Lists Here" tab in step 4?

That tab will only show up after the math trade organizer disabled new items being added to the geeklist, done a final resync of the OLWLG to the geeklist, and then genereated (and loaded) the official summary.

Step 3 only shows me some of the items...

The OLWLG by default will only display any items that were added since you last viewed the list (step 3) for that math trade. In this case the OLWLG informs you of this at the top of the page and gives you a link you can use to view the whole list (if a 1,000+ item math trade this will be a large page load).

Game stats don't exactly match BoardGameGeek

The OLWLG only get's new game data (this is the stats like designer, playing time, rank, number wanting/trading/wishlist, etc) for games it didn't already have that data cached for. It used to always do this but this was the slowest part of doing each re-sync as the geeklist got larger and larger.

The game data is fresh for each math trade however so don't worry it may be way out of date. The most out of data it can be is from the initial sync of the math trade.

Links to games not included?

Q: How do I include a link to a BGG game page in my listing that is not an item I'm including in my offering?
A: use (or similiar service) to create an alias link that will redirect to the game's page. For example, instead of or Metro


There was an experimental math trade where TradeMaximizer priorities are used to try to minimize shipping distances. Now it's useful to see distances and in multi-national math trades where games are being shipped from.

Yellow boxes in step 4?

Yellow is just the program's way of pointing out that you may have offered a game you seem to value more without offering a game you seem to value less.

How to remove an item I added in step 3?

Ok, for yuks I did a quick and dirty implementation of this and have tried it myself... quick and dirty as I didn't do it as I would have liked to, instead...

to delete an item while in step 4, table format, in the field for the item where you would normally enter an optional "value" to override the default ordering (see the olwlg wiki) instead of a numerical value put in the word:


all in lowercase, no leading or trailing spaces. When you submit the form those items will be marked deleted from your list. NOTE that no warning is given even if you have this item on your want list for any of your items (ie. there are any checkboxes checked in that row).

Again this is experimental... report problems to the discussion thread. You should in theory also be able to re-add in step 3 items you've deleted from your wants this way (haven't tried that yet even myself).

My collection data (wishlist, owned, etc) seems out of date

On the OLWLG "home" page after the list of "Active Math Trade(s)" it tells you when your collection data was last resynced and there is a link you can click on to force the OLWLG to resync it.
If you have a significant number of games (wishlist, owned, etc), the current (as of 26 April 2011) resync link will not work. You will get an error such as ...
"Fetching [your BGG ID] ... 106.06 Internal Error: Cannot allocate memory"
However, if you use the following manual link to directly resynch your data, then the memory error can be bypassed.
WARNING: there has been a report that this alternative script may end up with incorrect collection data for you within the OLWLG... if this happens to you too please use the normal script linked to on the main olwlg page.

Why do some items have photo icon and others don't?

the ones that do are geeklist items that the person offering the item has chosen a specific image and thus hopefully is an accurate representation of what is being offered. The ones that don't are ones where a specific image was not chosen and as such could cause confusion.

By the way if you haven't noticed if you click on the photo icon the icon is replaced by the actual image. Clicking on the image changes it back to just the icon.

Step 4 is really slow if you have a lot of checkboxes

There is an experimental option explained by JeffyJeff in newstyle Re: Math Trade Online Want List Generator (OLWLG) - Discussion, Problem Report, etc thread:

Ok, I've made some changes do do just this... you won't see them unless you edit the url to add an additional argument (details below)...

What this new style does is to not use check boxes at all in the table (step 4), instead what you do is simply click within the cell to toggle the simulated check box (when "checked" a green check mark icon will appear in the cell). Internally what it does is for only every "checked" cell create a hidden form input. So unless you have every box checked it should be significantly less for the browser to deal with.

It does seem some what faster to me. It also has another side benefit... if you have any of your items that don't want anything (ie. nothing checked in some columns) you may actually fit more columns on the screen (though trade off is those no want columns are skinnier)

In any case the argument you want to add to the url is newstyle=1, for example...


Let me know what folks think of this new style. If I could port CheckBoxMate to work with these mock check boxes then I may make it the default style.

Can't connect to OLWLG site or connection lost problems

OLWLG web page sizes are larger than most which sometimes bumps into router bugs. Check your router's firmware version and see if there is a newer version you can upgrade too. That has solved the problem for several other OLWLG users.

What are auto generated dummy items?

See "How to Offer Multiple Identical Copies/Bundles" bullet above

Only the main item is looked at for magnifying glass and duplicate protection?



Firefox plugin for checking/unchecking boxes

Firefox plugin for checking/unchecking boxes (dead link)

Firefox/Opera plugin for checking/unchecking whole rows/columns, and more

OWLito: An OLWLG helper

Chrome plugin for checking/unchecking boxes

Checkboxer for Google Chrome (dead link, redirects to

Cross-browser Bookmarklet for checking/unchecking boxes


Better OLWLG (Retheme and accessibility improvements)

Better OLWLG

Closing Note

And of course feedback welcome! And of course GeekGold tips always accepted if you find this tool useful! (but always make sure to 1st tip the math trade organizer [if it's not also me])

Who is JeffyJeff?

JeffyJeff is Jeff M.'s BGG username and the person behind the OLWLG.

Jeff Michaud
United States
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On-Line Want List Generator - Hopefully Making Math Trades a Little Bit Easier
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