Crabjack-21 - An update to the polyhedral dice gambling game

Crabjack-21 is a dice-based gambling game that uses a single set of d20/d12/d10/d8/d6/d4 dice, so it can make a nice fit for an RPG setting using something the players have on hand.  It's based of off Crabjack, but adds the d20 and has the payouts balanced to account for the extra die and higher total.

Crabjack-21 is played by a single player against the house, although any onlookers might make side-bets with each other about the outcome of any next roll.  The player makes their initial bet (within the house limits).  From now on the player is going to pick a die and roll it, adding it to their running total.  Each die can only be rolled once.  Depending on the total they are at, they will either win a payout (ending the game), bust out (ending the game), or have to keep rolling.

Getting an exact total (of all dice rolled so far) of 7 or 11 or 21 wins a payout.  The player busts out if they go over 21, having a total of 22 or higher.  If the player manages to roll all six dice without busting out, they win regardless of their total.  Some versions of the game (you can pick which version you like, or have multiple versions in your world representing local variants of the game) have special rule if you roll a 1 on the first roll:  It can immediately end the game (with or without a payout).

Here are a couple versions of the game, these all have a base payout of the bet plus half, and then a bigger payout for the 6-dice win:

(1st roll): Keep rolling
7 or 11 or 21 (1st to 5th roll): 1.5x
21 or under (6th roll): 2x

(1st roll): End game, lose bet
7 or 11 or 21 (1st to 5th roll): 1.5x
21 or under (6th roll): 6x

(1st roll): End game, but get half bet back
7 or 11 or 21 (1st to 5th roll): 1.5x
21 or under (6th roll): 5x

Outside of a casino-like environment, gamblers can take turns being the house.  They should agree on each taking the same bet and number of turns being player and house.  If played this way, you can can tweak the payouts to whatever you want, e.g. 2x on 7/11/21 and 10x on a 6-dice win.  Those higher payout numbers would make being the house all the time a losing proposition (with perfect play), but it doesn't matter if both sides take turns playing the same way.


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  2. thank you for this game, i like it. it is quick and simple with most games resolved within 3 rolls. if this was a between RPG time filler i would be inclined to use fairer odds, 50:1 for under 12. and 2:1 for 7or11 in the 5 dice game, 3:2 for 7or11or21 13:1 for under 21 for the 5 dice game, thank you. contact jonolio@hotmail.com credit to http://anydice.com