Cards as an RNG?

[Grek]

I've been toying around in my head with the idea of a western game which uses playing cards as the random number generator. I've heard that Deadlands used this for their magic system and used poker hands to do so. That seems somewhat iffy. Are there other games which use cards? Are they any good?

My current idea is that you'd have four attributes, Strength (hearts), Skill (diamonds), Wits (spades) and Will (clubs) and 10 talents divided equally into physical (red cards) and mental (black cards). In order to take an action, you need to play a card from your hand of the proper suite - a heart for strength checks, a spade or club for medicine, a diamond for skill and so forth. To succeed, your card has to beat the DC (difficulty card) to the task. Your talents and attributes enforce a minimum result, so if you play a card that is less than the relevant stat, it counts as being whatever your stat is instead.

Some special checks (like socializing, stealth and a few other things) require that you play a hand of blackjack against the DC instead, starting with a card of your choice from your hand and then drawing blind from the deck every hit after that. Others may involve poker hands, but probably not.

[rampaging-poet]

There was an indy RPG called With Great Power that used cards as an RNG. It's no longer available legally, but each player had their own deck of cards which couldn't be reshuffled until it ran out. This encouraged saving your high cards for when they really mattered because you wouldn't see them again any time soon.

In general, the feel of a game with card-based RNG depends heavily on how often you start from scratch (new hand, re-shuffled deck). Frequent deck turnover encourages using high cards right away because you'll lose them soon if you don't. Infrequent deck turnover encourages hoarding high cards and defaulting to your specialties as often as possible. With particular actions tied to types of cards, infrequent deck turnover also forces players to take actions outside their specialties: there are only 13 Hearts in the deck no matter how many they drew to start with.

The probability of having any given card or type of card greatly increases with hand size. My intuition says that a 5-card hand has a good chance of giving a range of options, but I haven't actually run the numbers on that yet.

The number of decks relative to the number of players is also an important factor. The probability of any given player drawing a king is the same regardless of whether they have their own deck or everyone draws from the same deck, but the probability of at least one player having a king increases sharply as the number of players rises.

I'll run some numbers on your proposed system shortly. If you'd like to calculate anything yourself, the probability of drawing a given type of card follows the hypergeometric distribution. If you're drawing n cards, it's (all the ways to pick k of the K cards you want) * (all the ways to draw n-k of the 52-N cards you don't want) / (all the ways to draw n cards).

[Grek]

I've been using this site to do my calculations. Initial math:

On your first draw of five cards with a fresh deck of 52, the odds of getting a card of a given suite and a value of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, ace, jack, queen or king are as follows: 78%, 75%, 71%, 67%, 63%, 58%, 53%, 47%, 41%, 34%, 27%, 18%, 10%. The same odds for a card of a given value and the correct colour are 97%, 96%, 95%, 92%, 89%, 85%, 81%, 75%, 67%, 58%, 47%, 34%, 18%. On average, these odds go up slightly as the deck gets smaller (on the order of less than 5%) but in play will depend strongly on what suites you've been using and whether you've been doing a lot of defaulting or not.

[Grek]

May as well post some background info here, if only to get it out of my brain. If it helps inform mechanics, all the better.

This is weird west setting. Which is to say, fantasy western. Think the Mysterious Gunslinger vs. the Zombie Cattle Rustlers. Cowboys with magic guns.

Setting info:
I am aware of Dead Man's Hand, but do not intend to use much of anything from it. For example, I will specifically not be using Frank's race write ups. I feel that having 19 playable species with their own special stats, stereotypes and background info is too much. I'm only looking at six races, tops. My current list of playables is Human (normal human), Revenant (undead human), Lycanthrope (cursed human) and Robot (artifical human). There will be a few non-playable sentients like Ghost (dead human in the underworld) and Underworlders (inhuman things that live in the Underworld). All names are subject to change.

Due to the existence of magic history unfolded differently than it did in real life. Highlights include:
-The European magical disciplines of Demonology and Katabasis allow people to use magic to travel to the Underworld, where the spirits of the discontent dead dwell alongside inhuman beings native to the region. In addition to the theological implications, the ability to speak with the dead has had the practical effect of significantly altering the justice system in Europe.
-Similarly, with travel through the Underworld allowing for safe (provided you don't cross international boundaries, which is forbidden by international treaty and armed guards at the main entrances to the underworld) and extremely rapid travel across great distances prevented the American colonies from being as isolated from England as they were in real life, ultimately adverting the American Revolution. Both America and Canada both became Commonwealth nations under the Constitution Act of 1867.
-Due to the previously mentioned difficulties in international magical travel, European expansion into North America was largely halted at the Mississippi River in the east once the native people figured out how to counteract the European's devil magic. Russian colonization attempts were similarly halted at the Rocky Mountains, ultimately resulting in California and Alaska being sold to America and Canada respectively. Thus, while the Infernal Railroad runs from the East to the West, there's no way to get into the heartlands of the continent without crossing the boarder into one of the tribal nations.
-Due to the Rain King's ability to call down rain (be it of water, of frogs or of fire) at will using effectious prayers and sacrifices, the Aztec Empire is alive and well. While the Empire has acknowledged the rights of the Spanish to settle throughout the Yucatan peninsula and Isthmus Panama, they continue to insist upon their own right to send war parties in to abduct non-Nahuatls for religiously obligated human sacrifices. In the New World, Spain currently only holds Florida, Cuba,and the Caribbean isles, while Portugal has control over Haiti.
-Louisiana is owned by the French, with the border between French and Aztec holdings having been drawn at the Red River. Aztec raiding of Louisiana is essentially non-existent compared to the daily abductions in New Spain. Rumour has it that Napoleon made some sort of deal with the Rain King, but nobody who knows the truth seems interested in talking.
-Abolition is currently on the way in, and Slavery on the way out. All of Canada and most of the northern states in America have banned slavery - the California Territory has voted to be a Free state once they gain statehood, and Southern representatives to the American Parliament are doing all they can to block California's entrance to the union, going so far as to threaten succession if they don't get their way.

Mechanics wise:
-Each player has a deck of 52 playing cards which serves as the primary RNG for the game. Success/Failure is based on what card you play. Every time you play a card, you draw a card. Injuries take away cards without letting you draw to replace them, making your hand smaller. A character is Exhausted if their deck runs out of cards. They default on all checks to the appropriate Attribute or Skill -2. Resting lets you shuffle your played cards back into your deck.
-As previously mentioned, a character has four attributes (Strength, Skill, Wits and Will) and ten talents: Brawling, Riding, Stealth, Survival, Toil for physical and Law, Doctoring, Cheating, Craft and Carousing for Mental. Attributes Checks allow you to negate or diminish bad effects by playing a card of a matching suite, while talents let you do things by playing a card of a matching colour.
-The actual number next to an ability defines your minimum competence. You can default to your Attribute number by playing any card of the correct colour or to your Talent number by playing any card at all. This gives a use for 2s and 3s that would otherwise not be good for anything. You still always have to play a card to default, and if you have no cards left in your hand, you collapse unconscious, unable to do anything at all.
-Each player also gets a tarot deck of 22 mana cards. These are used by characters who know magic to cast spells or by important non-magical characters as a combination of Edge and the Tome Fighter's Foil Action ability. Unlike regular cards, these don't have a value, can't be used for checks, aren't replaced as they're played and (usually) aren't shuffled after a rest.
-A nonmagical character can play a mana card at any time to negate the effect of a regular card that was just played. The player of the regular card has to play a new card or automatically fail the action they were using that card for. Nonmagicals draw one tarot card every time they draw a regular card, up to a maximum of 2 tarot cards in their hand. They shuffle their tarot deck by resting and are the only people that do so.
-Characters who learn magic trade out the above ability for the power to cast spells. Each of the ten magical disciplines has a Ritual (which is costly, dangerous or difficult) and an associated talent. Doing the Ritual recharges your magical mojo and lets you shuffle your tarot deck. Success on an associated talent check lets you draw one mana card, up to a maximum based on how well your most recent Ritual went. You can play the mana cards to cast spells.
-The magical disciplines and their associated talents are: Sacrifice(Brawling), Possession(Riding), Katabasis(Stealth), Hexing(Survival), Sanctity(Toil), Demonology(Law), Medicine(Doctoring), Fortune(Cheating), Artifice(Crime) and Voodoo(Carousing). Of these, Possession, Katabasis, Demonology and Artifice and chiefly European in origin, Voodoo is African, Sacrifice is Aztec, Medicine is Native and Hexing, Sanctity and Fortune are universally known.

[JigokuBosatsu]

This is the second time this week I've seen a mention of katabasis. Is there some pop culture reference to this that I'm not aware of?

[Whatever]

The main problem most games have with using cards is that they're much more expensive than dice, especially if you want decent quality. That's not the case if you're just using a standard deck of 52 playing cards, but that doesn't mesh with the flavor of most games. Wild West themed stuff is probably the biggest exception to that, because playing cards can fit in well with that setting.

[Grek]

This is the second time this week I've seen a mention of katabasis. Is there some pop culture reference to this that I'm not aware of?

Katabasis refers to a trip to Hades. Like in the story of Orpheus and Eurydice, or Odysseus going to talk to Teiresias. It's Greek for "downward (kata) travels (basis)". It can also refer to going down a river, but that's a lot less common.

[JigokuBosatsu]

I know what it is- I'm just assuming that most people don't, so was wondering if something was out there more recently than Iron John. The only guess I could make was maybe the covered-in-ashes bit from God of War, but I haven't played it so... dunno.

[...You Lost Me]

Katabasis refers to a trip to Hades.

Awesome.

[Manxome]

Assuming that you have a "hand" of cards, and can therefore choose to "save" some cards for future checks, it is incredibly important to say exactly when you can draw more cards, and under what circumstances (if any) you are not allowed to save cards. Because anything the player can do to draw cards is now a resource-generating action, like resting to recover HP/spells/whatever, and therefore needs to be balanced as such.

For example, your first thought might be "whenever you play a card, draw a new card to refill your hand." This means that players will attempt tasks that require a skill check when they don't actually care about the result, just to get rid of their bad cards. "I jump up in the air for no reason," "I try to beg a copper piece from some random guy in the street," "I search some tree we're walking past for secret compartments." Until your hand is all aces.

So at this point you probably counter with "you draw a hand of cards when you enter a situation where you would not be allowed to take 20, and discard any leftover cards when you are no longer in such a situation." And that could maybe work, as long as you keep in mind that anything that results in a skill check has to have a cost at least high enough to justify its use as a "draw 1 card" resource-management tactic. Can I drop a crappy card and draw a new one by: making a social, perception, or knowledge check mid-combat whose result I don't care about? Leaping, tumbling, or balancing unnecessarily as part of my movement? If so, then you'd better expect players to do that sort of thing on a routine basis. See also: bag of rats.


Rather than drawing a card whenever you use up a card, you could do something like "at the start of each round, draw 2 then discard down to your hand limit--no refills before then." Then there's no advantage to spending extra cards, and if you can possibly make more than 2 checks in a round there's a potential advantage to conserving them (and you need a rule for what happens when you have to make a check but your hand is empty). This also means that you get lower average RNG results when you make more than 2 checks per round, which could be a cool tactical element (e.g. if you have to play a card to defend against an attack, then when many opponents attack you at once you run out of cards and are forced to start defaulting--automatic flanking bonus!).

Of course, players are still going to try to spar or something while they're waiting in ambush so they can build up a great hand before the real combat starts--then again, maybe that's OK, and you just have a rule that you get to pick your starting hand if you've got time to prepare for a specific task.



Your idea of using different suits for different attributes has the additional problem of "what happens if you don't have any cards in the suit you're supposed to play?" If you've got any sort of specialist who uses one attribute even slightly more often (on balance) than the other 4, he'll eventually run out of that suit (actually, even if you use all 4 equally, you'll eventually get a run of useless draws by poor luck; specialists just get it a lot more often). This might not be a huge problem if you reset your hand often enough, but it's definitely something I'd be worried about.

You might consider saying that you can use any suit for anything but using the correct suit gives you a bonus.