VASSAL: A Virtual Army of Conflict Sims In One Client

If you want to play a board game, one of the most essential ingredients is someone to play against. I found this out the hard way as a first-time parent, house bound by the demands of a baby and drained of energy but not my feverish appetite for gaming.

That’s when I discovered VASSAL. It’s a freeware, open source Java program that lets you play boardgames over the internet, either live or via email. And not a narrow selection, either: each game requires that you download a specific module, and the official site alone lists over 1,300 of them. There are more out there in the wilds.

At the point of succumbing to child-induced cabin fever, I was suddenly free to choose from this bewildering library of brilliance and play games as slowly as I wanted without ever leaving the house. There were games I already owned, games I wanted to try, games I’d never heard of but sounded superb; all at my fingertips alongside an army of eager opponents.

Monster Games

It’s a situation that Joel Uckelman, the project leader on VASSAL, understands well. “If I want to play the full campaign in DAK II it would take weeks,” he tells me. “I’d have to keep our two-year-old daughter and two cats away from the kitchen table that whole time. It’s a great way to accommodate large, long games.”

DAK II is a monstrous military simulation of North Africa during World War Two, with 1500 counters and five 22” by 34” maps. It’s not hard to see why anyone wanting to play it might prefer to do so on the convenience of their computer desktop. It’s also representative of the bulk of games that can be played on VASSAL, most of which – though not all – are conflict simulations of some kind.

Joel lets me in on a particular reason, beyond the administrative advantages, why this should be so. “VASSAL began as VASL: Virtual Advanced Squad Leader. It was just for ASL, not a general program for playing board games,” he says. “When VASSAL became a separate project, it had the capabilities you need for games with stacks of square pieces on a hex grid – i.e. classic wargames – but not much else. Support for things like cards wasn’t added until later, so wargames had a head-start.”

Faceless Opponents

This helps explain another anomaly. Board games are traditionally viewed as primarily social experiences, giving players the chance to glory in the startled expressions of their opponents before laying the smackdown. Moving them online seems inherently contradictory. But wargames tend to be slow, heavy, two-player affairs where the social dimension takes a back seat.

Nevertheless, Joel agrees they’re better played face to face. “My grandfather always said that to get something, you have to give something up,” he says. “But it’s not a question of VASSAL replacing face-to-face play. Any game I play using VASSAL is a play I wouldn’t have had otherwise.”

And, as he points out, the experience has its compensations. “I’ve never clumsily knocked over a stack of pieces with an errant die roll in VASSAL, I can think as long as I want about a move when playing by email, and I have a log of the game when we’re done.”

Whatever its shortcomings, it’s become incredibly popular. Joel’s been on the project since 2006, but it was originally released in 2003 by Rodney Kinney and has gained a devoted following. Joel goes so far as to suspect that “the vast majority of wargames are not played live.”

Legal Loopholes

But since VASSAL is free software, and the majority of the game modules available for it are fan-made and released for free, it would seem to be on rather sticky legal ground even though the terms and conditions specify that users must own a physical copy of the game. I presume that Joel would know a reasonable amount about copyright law, and he doesn’t disappoint.

“There is, to the best of my knowledge, no jurisdiction in which it is illegal to *produce* VASSAL modules,” he tells me. “Copyright law in the US, at least, tends to be about distribution, not production. But I can hardly see that it would be worthwhile for anyone to go to court over any of this, since we remove modules from the site whenever asked.”

This does happen. I’m aware of at least one publisher, Fantasy Flight Games, who dislike people making VASSAL modules for their games. But does it happen often? “Seldom,” says Joel. “It happened once or twice last year.”

Is it permitted because most users do own a copy of the game? “It’s typical that some players don’t,” admits Joel. “But I don’t see a substantive difference between playing in person and playing using a computer in that regard.”

The only option left is that publishers benefit from VASSAL in some way. This is what Joel believes. “If none of the players owns a copy of the game, I would hope that the experience leads some of them to buy the game,” he says. “There’s anecdotal evidence for this: you can find loads of posts on BoardGameGeek where someone says they played the game on VASSAL and bought it because they liked it so much.”

Is VASSAL treated by publishers as free marketing? Joel thinks so. “The rational approach is to consider people playing games they don’t own as free advertising,” he tells me. “Some people who would not have otherwise had the opportunity to play your game might play it in VASSAL and go on to buy a copy, and those who persist in playing without buying a copy weren’t going to be your customers anyway.”

Competitive Games

Since the use of client software to facilitate games via email is not only legal, but positively encouraged by most publishers, it’s not surprising that VASSAL has some competition. The best-known is probably the windows freeware program Cyberboard which has been around since the mid nineties, and there’s a new kid on the block called ZunTzu.

But VASSAL remains the tool of choice for most gamers. When I ask Joel what he thought it had over its competitors, his reply is clear and immediate: “It’s cross-platform, it’s open-source, and it’s not a one-man operation.”

He’s a big fan of the open source philosophy. “I don’t want my virtual tabletop software to dictate my choice of operating system or opponents, and I’m not alone: 15% of our downloads are for non-Windows builds,” he tells me. In fact, as a Linux user, he first got involved in the project out of a desire to play games online against Windows-using friends.

But it’s as much about the collaborative power of open source as it is about stepping away from commercial operating systems. “It’s easy to get burned out when a project is your sole responsibility,” Joel points out. “Because VASSAL is open-source, anyone with the necessary skill can lend a hand. I know of at least 29 people who have written code for VASSAL.”

That critical mass of people provides the underpinning for an active community. “There is daily activity in our forum,” Joel tells me. “We have an IRC channel (#vassal on which has some regulars who are willing to help. If you have a question about or a problem with VASSAL you can usually get a reply, if not always a solution.”

History has a Future

It’s the sort of snowballing effect that many open source projects only dream of, where motivated programmers support an active community which in turn encourages an expanding user base from which new people can be recruited. With so much magic in the air, there were bound to be exciting plans for the future of the software. But I wasn’t expecting anything as big as the details Joel confides.

“Java is becoming increasingly decrepit,” he tells me. “And we’ve been struggling for years with some design limitations of VASSAL. We’re addressing both problems at once with VASSAL 4 by switching away from Java.”

An entire platform switch is a big goal for any project, but Joel is intent on shoehorning in more features at the same time. It’s not a trivial list, either. “Among our goals for V4 are a simpler, modern graphical interface, an embedded scripting language which is not VASSAL-specific and persistent remote storage of game state.”

There are other goals, too, and it’s such a colossal wish-list of feature that I can’t help but worry that it could be crunch time for the project: an overly-ambitious set of goals that could lead to burnout and despair. That’d be a small personal disaster for me, and for thousands of other gamers who’ve become addicted to the mystical way that VASSAL lets you re-create history with strangers on the other side of the world.

But Joel seems reassuringly confident. His belief in the power of open source programming and his obvious commitment to the project come through loud and clear in his answers. VASSAL is probably the most-used piece of software on my PC, more than office programs, more than Steam. But if there’s anyone I reckon I’d trust to look after it, it’s Joel.


  1. SillyWizard says:

    What is a Matt Thrower…?

    • CookPassBabtridge says:

      Someone has hacked into RPS and posted A USEFUL AND INTERESTING ARTICLE. Man the barricades, change your passwords. Blame Anonymous.

      We will accept this “Matt” if he will grant us one wish: Endless pictures of plushies. Thats what Cassandra did anyway and it worked on me.

      • SominiTheCommenter says:

        I don’t trust anyone with three T in his name. Consecutive even.

    • jonahcutter says:

      It’s complicated, but suffice it to say that there are several people named Matt currently enjoying escape velocity and headed for the Oort Cloud.

      • LionsPhil says:

        Given this telemetry data, I’m not sure about “enjoying”.

        I didn’t think it was actually even humanly possible to scream for that long.

        • jonahcutter says:

          Oh dear. Well, perhaps we should keep the audio feed switched off. Wouldn’t want to upset their families.

    • Tams80 says:

      An acronym perhaps? We must decipher it. Go Hive Mind!

      • TWChristine says:

        I’m not sure about acronyms, but I did notice that if you drop three letters from the last name you get Thre. Then if you drop a letter from the first name you get Mat, and if the “t” that you dropped gets bent over in the process of transferring over to the last name it could make an “e” which would give you Mat Three. You now have THREE letters in the first name, with the obvious Three of the last name.

        ….I’m not sure what that signifies..maybe a new Candy Crush game or something..

      • Dances to Podcasts says:

        The initials are M. T. and there are three t’s in the name, in a row. There can be only one conclusion. It’s Mr. T.

    • Darloth says:

      A little late to the party here but since you phrase it that way:

      “A miserable little pile of throw rugs”

    • wwwhhattt says:

      A creature too powerful for the confines of Shut Up & Sit Down.

    • Nice Save says:

      Now that they have officially hired Graham Smith and thereby made him a real person, they now need another made up person who can post articles and leave us mildly confused as to what’s going on. Shame his surname isn’t Smith or he might have had a chance at manifestation.

  2. pakoito says:

    Some day someone will realize you can play hundreds of boardgames over VASSAL, from ye olde Space Hulk to Netrunner or Summoner Wars.

    • Viceroy Choy says:

      Netrunner online? Yesssss

      • JustAPigeon says:

        It should be noted that there are better options than vassal for playing Netrunner. Look up Octgn, there’s a tutorial and stuff. Wait, here it ls: link to

        • Harlander says:

          I really wanted to try the VASSAL version of Car Wars… <.<

      • gwathdring says:

        Is there even a VASSAL module for new-Netrunner? It should also be noted that in order to comply with various games company policies (in particular Fantasy Flight), VASSAL modules sometimes have some sort of card-text spoiler meaning you have to do some additional googling/piracy/purchasing-of-board-games in order to properly use the module. This is by no means true of all modules, but it is true of almost every single Fantasy Flight module.

        It is notably not true of OCTGN games including Fantasy Flight’s Android Netrunner.

  3. ElErecose says:

    Not to mention all the Tabletop Support for Vassal!
    Where games like Warhammer, Warhammer 40000, Warmachine / Hordes and all the other smaler ones can be played.

    I for myself play a game of Warmachine once a Week with a friend, who lives in another city. Skypetalk includet, it’s a great way for tabletop gaming when you can’t play in one place…


  4. Bull0 says:

    Hey wow, it’s the thing I used to use to play warhammer like, six years ago

    • Geebs says:

      Just out of interest, given that GW doesn’t exactly have a reputation for being relaxed about their brand identity – how?

      • Lengle says:

        It was called Vassal 40K IIRC. Not sure if its been killed by GW yet, or if it is still a thing. My work laptop is giving me grief on the search.

        • Rev_Sudasana says:

          GW made a stink about it a while back, but you can still find it pretty easily through a Google search or similar.

      • Bull0 says:

        Yep, fan-built module Vassal 40k. Lots and lots of fun, but the current 40k rules are a bit weak, so I lost interest. You should still be able to find it if you look hard enough, I think a few of my mates still play. 100% unofficial, and yes, GW are doubtless flooding the internet with probe droids to try and find it and crush it.

        *edit* there we go, thanks a lot Phuzz for the link!

  5. The Hairy Bear says:

    I’m assuming this is the same Matt Thrower from shut up and sit down which is very cool. I do like vassal having mainly played 40k over it (answer to Geebs, GW doesn’t approve of it much!) but I would certainly agree it would never replace the face to face experience. That said Battlefield Waterloo by my rough approximation would have required me to be at my friends house for approximately seven months by now so it certainly has its merits…!

  6. Warduke says:

    RPS needs a Vassal forum.. Would be awesome to take advantage of the large community here to get in some virtual table top gaming.. Who’s with me??

  7. Tusque D'Ivoire says:

    How ’bout an RPS, SU&SD, Crate&Crowbar and NotAGamePodcast supergroup? Yes, Nick Mailer from Rum Doings, you can come, too (though you won’t want to).

  8. joshg says:

    “There is, to the best of my knowledge, no jurisdiction in which it is illegal to *produce* VASSAL modules,” he tells me.

    This is hopeful thinking, but pretty much wrong. If you copy materials (text, images, etc) from an existing board game without permission, which presumably is exactly what you’re doing when producing a module that clones an existing game, then you’re breaking copyright. It’s a derivative work, you could maybe argue that it’s justified, but if they bothered taking it to court then I doubt you’d win.

    If you’re making a module that plays identically but you create all images, text, etc yourself, then you’re in the clear. Unless you use the existing game’s original title, in which case you’re in trademark law territory.

    This only lives on the fact that board game publishers don’t have unlimited money to spend throwing lawyers at people who are making free stuff. But, they might. (And they sort of have to at some point to defend their work.)

    * I am not a lawyer! I just studied this a couple of weeks once.

    • Malfeas says:

      It’s not a complete game. It’s more a virtual board or table with virtual tokens. It basically allows you to play, if you own the rulebook. In games that have an event deck or something like that, the decks usually aren’t provided in any way, you still need those, too. So, while theoretically possible to play it without someone having the physical game, it would require additional effort to do so and thus use this tool illegally.
      Funny thing is that especially FFG’s games are pretty safe, considering they usually have a lot of cards you can’t play without, but it’s their decision *shrug*.

      There are no rules being enforced in most of them, and the art varies immensely. Some is simply scanned in art from the original, but most I’ve played with are using new art made in the image of the original, but not a straight up copy. Some use this as an opportunity to make the tokens prettier, other, less artistically endowed people, end up drawing stick figures and numbers ^^

      So basically, yeah, it can be argued to be derivative work or even downright copyright infringement in some cases. So if a publisher asks them to remove it, they’ll do so (regardless what the law would state) just to be on the safe side, anyways. But most either don’t care or see the benefit. We’ve been living in an age in which “copyright infringement = damage to copyright holder” hasn’t been always true for a long time. There’s a big area in which you can infringe on copyright and yet support the copyright holder. See cosplayers at conventions, for example or a lot of machinima.
      Let’s hope it stays that way :)

    • cckerberos says:

      I’m not a lawyer either, but I think he’s more-or-less right. You’re right that any module created would be a derivative work and falls under the copyright held for the original game. But as long as the module was made only for personal use, it seems like it would be similar to the right (in the US at least) to create a backup copy of something. The problem, as he said, lies in distribution. The first time you send the module to someone else, then you’re in violation of copyright.

      • uckelman says:

        That was my point about production versus distribution, yes. Distribution without permission isn’t so clear-cut as the post to which you’re replying makes it out to be, at least not in the US. The Copyright Office itself says that the copyrightable parts of a game are the art and rules text, not the game itself.

    • MellowKrogoth says:

      So, what’s your point? You’re just showing off your legal knowledge, or you’re proposing we shut down everything right now because it might be not fully legal and only tolerated? Because IP laws are always right and we should let them dictate everything we do, right (just go over and read the article about trademarking Candy, then…)?

  9. Malfeas says:

    I’ve been using vassal for years to play Warmachine with my friends, who live over an hour’s drive from where I live. It’s also great, because I can play factions I don’t own a single miniature of, since I can use virtual versions on Vassal.
    Being able to do that, has led me to purchasing every faction book, so I can play them in vassal. That’s still 9 more faction books than I’d have gotten otherwise, and that’s already assuming I’d have cracked and purchased 4, rather than the two I originally intended to stick to. It’s also made me enjoy playing factions I didn’t expect, which made me get miniatures of those, as well.

    We’ve also taken to using it for some of our rpg games, though we’ve switched to roll20 in the meantime.

    tl;dr: My friends and me live far apart, couldn’t play with them otherwise. Invested more money than I would have for more options due to Vassal.

    Whenever I consider buying a board game, I go look if there’s a Vassal module for it. If there is, the likelihood of me buying it goes way up.

  10. LordDamien says:

    My wife peeked my screen and though I was trying to access a web named “”. Many thanks Vassalengine!

  11. HothMonster says:

    Now the site is down, are you happy now Matthew?!

    • uckelman says:

      We’re working on fixing that presently. The huge upsurge in web traffic exhausted our server’s RAM.

      • uckelman says:

        The site’s back now. We were not prepared for that kind of load.

        • HothMonster says:

          :) figured. DDOS of love. That is why I was yelling at Matt and not you, all his fault.

          • Matt Thrower says:

            I feel bad about what happened, but I couldn’t really have predicted it. Would you rather people not know about this amazing piece of software, and that Joel and co keep skimping along on a small donation pool?

  12. drewski says:

    The RPS horde strikes again.

  13. Zmobie says:

    Apparently GMT Games is on-board with the idea of VASSAL acting as a free marketing tool, having modules for download on their own site (they also have modules for other software such as ZunTzu and Cyberboard) link to

  14. NightSod says:

    Vassal is amazing. “Mage Wars” was recently made into a module, a fact that is almost certain to cost me £50 or so, now that I’ve had chance to faff about with the module. Likewise, that happened to me with “Memoir 44” and “Summoner Wars”.

    Unfortunately, Zuntzu (which was shaping up to be really promising) and “Zuntzu II” have been in limbo for the best part of a year…

    …and a RPS Vassal group is a super idea.

    • Warduke says:

      I’d love to see an RPS Vassal group, a community like this and Vassal seems a match made in heaven

  15. Kohlrabi says:

    I have played quite a share of Twilight Struggle matches using Vassal, that module is done very well and even implements most of the rules and does the housekeeping. With most other modules you have to do that yourself, which can be quite annoying due to how the UI of Vassal works.

  16. malkav11 says:

    I don’t know that it’s accurate to describe FFG as “disliking” VASSAL adaptations of their games when they have in fact explicitly okayed them with the proviso that some game text should be omitted so that it’s necessary to refer to an actual physical copy of the game (or probably some internet database somewhere) to play via VASSAL.

    Compare to Games Workshop, which actively makes people take down VASSAL modules for their games.

  17. v21v21v21 says:

    The bottom line is, if you are a board gamer and you try out a game on vassal and you like it, you WILL buy it. As simple as that. It is part of our affliction. No escaping it. Because, that’s what you are, in this digital age. You want to have that actual, physical copy in your house, slide off the top once in a while, finger the components, set it up when wife and kids are are not around, perhaps sigh, and then put everything back in and shove it back into the closet. Waiting… For when the kids grow up, the wife agrees to give it a go or, lo and behold, you find yourself with a buddy who “gets it”.

    So, vassal lets you test drive and, honestly, saves you some money from those games which may be great, but not for you.

    What GMT does is good, in a way, although their games usually require a scenario book which they normally do NOT provide online. Not too much different from FFG, though less insulting.

    I actually got Twilight Struggle after testing it on vassal only, solo and, following, with my buddy.*
    I got Dominant Species after soloing on vassal and presenting it to my wife, who amazingly, grew fond of it, on vassal. **
    And, yes, thank goodness, steered away from some would-be-regretted buys.

    Therefore, three cheers for vassal, and may lawyers eat bile ;)
    * since it was out of print at the time, even preordered it from GMT (P500)
    ** even got Origins:How We Became Human, which really clicked for me, after checking it on cyberboard. Which introduced me to three other Eklund games, two of them which I also got. (Hey, I’ve got three kids which someday will be old enough to disappoint me by not wanting to play… :D)