In a DnD 3.5 universe, could a spell such as Divination or Commune allow the caster to cheat at betting on sporting events? (For example, by asking a question like "Will Stan Stormbow win in this gladitorial match").

Is there any in-universe way around this, such as a abjuration that could be cast on the arena to prevent such divinations?

  • \$\begingroup\$ Hi David, welcome to the site! Which universe, there are many settings written for D&D 3.5? Also, take a look at the FAQ when you have a chance? \$\endgroup\$
    – C. Ross
    Mar 13, 2012 at 19:41
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    \$\begingroup\$ While this is in a homemade universe, I think the same problem and solutions would apply to any setting (unless you can think of a counterexample) \$\endgroup\$ Mar 13, 2012 at 22:23
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    \$\begingroup\$ An on-topic comment: Star Wars Saga Edition (page 47) has a pretty great system for gambling. Might be worth checking out once you get your magic-interference resolved. \$\endgroup\$ Mar 14, 2012 at 20:01

8 Answers 8


Offhand, I'd say very well (ba-dum-tish).

There's a couple things that limit this; usually if Vancian magic is used, you wind up with this idea that you can only win a very small amount; you could gamble but you'd have to try a ton and it would be unwieldy.

If abused, here's some things I'd use as a GM:

Divine disfavor: If the person casting the spell is of Lawful alignment or Good alignment, their god may frown upon rigging gambling.

Divine fallibility: Gods can't be bothered to concern themselves with gambling, and just don't care enough to answer coherently/certainly/accurately.

Hidden error: Technically the spell description says that the caster can know, but if they abuse it they lose this ability (too used to the reactions, don't recognize truthfulness anymore).

Fate gaps: Not everything is guaranteed to happen as divination states; if the match were rigged, for instance, the pit boss may change the outcome at the last second, but when the diviner asked the first person was going to win.

Wards: I'm not familiar with this in d20 (according to Order of the Stick such things definitely exist, and I've read something about similar things but don't recall exactly), but you can get wards to prevent a clear reading/cause a false answer to be apparent.

"Mean" GM (ambiguity): I had a Shadowrun group that depended way too much upon divination, so I let them use it like a GPS to find mission objectives. They didn't know it was hidden in the room with a fake clearly planted, so they took the fake and ran off. This doesn't work so well for sporting matches, but you could focus on a trademark style and then the opponent happens to use it in the next fight, so on and so forth.

Material cost: Thor wants a cut of his cleric's gambling earnings, increasing the Cleric's material cost for Divination/Commune.

Not all of these fit very well in universe, but they're what I use.

  • \$\begingroup\$ A god of Lawful alignment might heartily approve of rigging gambling. \$\endgroup\$
    – psr
    Mar 13, 2012 at 21:48
  • \$\begingroup\$ That is true; but at the same time others would care. Similarly, one could make the argument that certain Chaotic gods wouldn't approve of rigging things either. \$\endgroup\$ Mar 13, 2012 at 22:41
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    \$\begingroup\$ In fact, one could make the argument that a lawful god might actually approve of the use of divinitation, as diviners knowing the outcome of the event (and betting on it) would reduce the rewards given to the kind of gambler who's in it for the thrill of uncertanty, and therefore a proponent of chaos. \$\endgroup\$
    – GMJoe
    Mar 14, 2012 at 4:48
  • \$\begingroup\$ Nice use of a rimshot! \$\endgroup\$
    – MadHatter
    Jul 22, 2012 at 8:42
  • \$\begingroup\$ Great answer. In addition to all that, its worth noting that in most DnD type settings, magic users are quite rare, and mid-high level ones even more rare. \$\endgroup\$ Jul 23, 2012 at 15:24

Mordenkainen’s Private Sanctum (p256 PHB) gives you a private area where divination spells can't penetrate. Nondetection (p257 PHB) cast on the participants in the gambling would prevent divination spells on them working. Combining those spells with some sort of enforcement to prevent spellcasting in the area, or an Antimagic field(p200 PHB) would help stop spellcasters rigging the event.

Another option is if someone had a "big win" the same spells you quote in your question could be used to check if the winner is a cheat. "Did Carl Crusher use a spell to choose the winner?" or something similar.

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    \$\begingroup\$ I like that counter-divination idea. That would be pure awesome. "The gambling board guy comes over and taps you on the shoulder. 'Sir, I'm going to have to ask you to leave.'" \$\endgroup\$ Mar 13, 2012 at 20:04
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    \$\begingroup\$ The problem is that Commune circumvents the spells you gave, since the answers come directly from your God. And unless the gambling board is casting Commune on all its big winners, a simple Nondetection of your own would keep your cheating from being discovered. \$\endgroup\$
    – dlras2
    Mar 13, 2012 at 20:19
  • \$\begingroup\$ Commune's 25 GP to cast, plus a 9th level or higher cleric. Not quite impossible resources, though it's a little. \$\endgroup\$ Mar 13, 2012 at 22:43
  • \$\begingroup\$ @KyleWilley Or 25GP and a magic item. \$\endgroup\$
    – aramis
    Mar 14, 2012 at 4:27
  • \$\begingroup\$ Mordenkainen's private sanctum would also mean that anyone looking into the area from outside "sees only a dark, foggy mass." That would put a damper on your average gladitorial match. And if the audience is included in the private sanctum, I think they would still be able to use divinations (it can't penetrate from outside, but the spell doesn't say anything about divination spells cast within the sanctum fizzling) \$\endgroup\$ Mar 14, 2012 at 14:56

Something like this is essentially a problem of a self-limiting nature. That is - gambling in this world is only done on things where there is some degree of unsurety regarding the outcome. The person/group accepting the bet will only do so if they believe that the person placing the bet does not have some form of superior knowledge regarding the event that they are betting on.

In the case of a world where divination magic is commonplace (or relatively rare but still well-known to those who would accept bets) you would expect bets just not to be taken unless there was some surety that an event could be protected from divination magics. Where there was betting it would tend to be between trusted parties or amongst groups where the idea of magic being used is far-fetched (for instance, amongst peasants if magic is a tool of the educated classes). As a result, getting into such circles could be a significant task (and adventure hook) in and of itself.

Protecting against divination magics? There's got to be a ton of spells in d20 for that. If not, just make up one. Say something with a decent radius that just disrupts divinations targetting events that happing within range whilst the spell is up. Rather than just block them, have it make the results just utterly unreliable. Sometimes the spells work, sometimes they give plausible false information and sometimes they just tell you that the gladatorial contest is going to be won by a carrot :) If you keep the duration of the spell fairly low it should prevent it impacting too much on other areas of the game.

Another possibility is to have the characters realise repeated success at their bet-fixing. Have them win a whole cartload of gold from all sorts of disreputable types with short fuses and low morals. Once word gets around that some spellcasters have been liberating the hard-earned cash from the underworld of a few cities/countries/whatever let them feel the consequences of the coordinated action against them.

It might also be worth noting to the players that they might make more money selling their spellcasting services to the local authorities, guild, nobility etc...


In sufficiently low-magic universes, the answer might be that divination does ruin gambling - but that magical methods of cheating are also so rare that they're rarely a problem and generally aren't worth protecting against.

If someone does seem to be winning more than the odds say they should, there's some simple methods of dealing with it that work regardless of whether it's magic, slight-of-hand, or just luck: First, make a big thing out of it. The publicity of a big win will attract gullible punters, and (as an added bonus) could lead to the big winner being jumped in an alley, putting an effective end to their winning streak. If that winning streak gets out of control to the point where it cuts into the house profits - well, then perhaps that alley-jumping incident could be arranged artificially...


Divination spells have some pretty significant built-in limitations. You're getting answers from a powerful extra-planar entity, who's most likely not going to be very happy to be called on regularly to improve your odds at gambling.

The "purpose" of these spells, in-universe, is to keep clerics on the right path in advancing the goals of their deity, and to keep them from dying unnecessarily from bad decisions that could have been easily avoided. If there's no clear connection between the question and the deity's greater interests, you can certainly expect a less-helpful answer. The SRD says, of Divination:

The advice can be as simple as a short phrase, or it might take the form of a cryptic rhyme or omen.

Commune is a 5th level spell (same level as Raise Dead). Using that kind of power for personal gain would certainly get you in trouble from a Good deity.

  • \$\begingroup\$ ... an Imp can cast Commune 1/week. That gives me a hilarious idea for a low to mid level game, in which the PCs are hired to put a stop to a run of bad luck by a gambling establishment, finding the Imp responsible. \$\endgroup\$ Jul 8, 2020 at 20:21

Games of Chance

There are several issues...

  1. Communication of hidden knowledge to players
  2. alterations of the objects used
  3. detection of hidden states
  4. compulsion of players to take undesirable actions

The simplest method is having a wizard enchant an anti-magic zone (AMZ) on/around the tables. This solves them all.

  1. No spells of communication work into an AMZ
  2. No spells of transmutation will work on objects in an AMZ, even if enchanted into the item.
  3. Spells of divination won't work on current states within an AMZ.
  4. various compulsions, including charm person, fail upon entry to the AMZ, and new ones can't be cast on persons within an AMZ.

Now, divinations may work, but if a mch larger enchantment of Mordenkainen's Private Sanctum is present, and the tables are bubbles of AMZ within... you've solved the detection of event resolution, as well.

You still have the issue of cheats and sharps, but those can be handled at the door with a variety of spells. An enchantment of aura of truth on a portal, and the gate asking "Are you intending to cheat in any way?" will solve many of them.

Sports & arena games

Sports book is similar. While it's not practical to put the arena in a DMZ, the gladiators can be kept in quarters of same. The Entire arena can be theoretically enchanted as such, but it might be a problem for magical duels; a larger enchantment of Private Sanctum would be suitable for the arena itself; an antimagic shell (AMS) around the arena's workspace separating it from the spectator space prevents interference in the event. Note that an AMS allows spells inside, and spells outside, but not crossing, thus allowing magical duels.

Put similar questioning aura of truth enchantments at the betting booths, and ask if the bettor has used any divination magic to find out about the events, and ask if they have any intention of attempting to influence the outcome.

Note that individual bookies will have done their best to divine the outcome anyway. Hence the gladiators being kept in nice but magically shielded quarters.

  • \$\begingroup\$ Of course, having an AMZ in a gladitorial arena would be pretty unfair to any battling spellcasters :) but otherwise I see the appeal \$\endgroup\$ Mar 13, 2012 at 22:25
  • \$\begingroup\$ @DavidRobinson Use an anti-magic shell, instead, and they can still zap each other, AND can't hurt the audience. \$\endgroup\$
    – aramis
    Mar 14, 2012 at 10:01

Well, going back to The Order of the Stick, just make a Cloister type spell that prevents all divination over a wide area and all subjects there in (albeit limited to block the most common spells for cheating in such games.)

Also it depends on where you are, a high magic area will take into account such things and have many layers of counter measures, a low magic area will do what they can within their means, and places where magic is practically non-existant generally won't care...though they'll also probably not let an obvious (or believed) magic user even participate.

Also, as shown put forth in the dungeon master's guide, inns or taverns might have anti-divination counter-measures or rules against such things so their patrons can relax and/or gamble in peace without worrying about having their minds read etc etc.


From my understanding of how gambling works in real life, there are two possibilities, and both will exist in different places.

  1. Cheating is prevented

People who run casinos are smart and are highly motivated to prevent themselves from getting ripped off. They will find ways to prevent magical cheating. It might still be possible to cheat, but doing so would probably be an adventure in its own.

  1. Cheating is common, and you're the victim

If you don't know who's getting ripped off, the answer is that it's you. Every alleyway dice and shell game that packs up as soon as a city guard notices is rigged frontways and back by means magical and mundane. It might be possible to outcheat the cheaters with some magic of your own, but actually collecting your winnings from them after is another story entirely.

This is how I would flavor gambling in a typical fantasy setting, but depending on how high magic or unique it is you could come up with all kinds of other stuff. Maybe high-stakes poker games in your world are played with the assumption that all other players are reading your mind at the same time, just like how it is in our world with body language. Maybe instead of betting on a horse race, rich landowners bet on how many serfs will get eaten by dragons each year, and your group has gotten into a nobleman's bad books by saving too many people and throwing off his bets.

The best thing to do is get creative. The less something is directly analagous to something in our world, the less players will question the logic of the situation.


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