Short Deck Poker comes in two versions: Six plus Holdem and a Triton variant, popularized by the ultra-high stakes Triton Series, which hosts live events several times a year around the world. The two versions differ in their hand rankings; both rank a flush higher than a full house, but the Triton variant retains the primacy of a straight ahead of three-of-a-kind. The other version, spread on some online sites, ranks three-of-a-kind above a straight in an effort to keep rankings consistent with the relative frequencies of the made hands. To add to the confusion, Pokerstars has chosen to call its Short Deck offering, “6+ Holdem”, whilst retaining the hand rankings from the Triton variant!
5-card poker hands are usually ranked inversely to the probability of making such a 5-card hand. With a Short Deck, the probability of making a given 5-card hand with a random starting hand is as shown below. Notice that straights occur significantly more frequently than three-of-a-kind in Short Deck Holdem.
The process of choosing the best 5-card hand rankings to use for a Short Deck game is not trivial. The table above shows that two pair occurs more frequently than one pair, yet one has to consider that a Short Deck board will pair 66% of the time by the river, compared to only 49% for the Full Deck cousin. This is not as inconsistent as it may initially seem; if the board remains unpaired by the river, then the probability of making a natural two pair is only 6.2% whilst the probability of making exactly one pair is 14.5%. Reversing the order of one pair and two pair to fall in line with the ‘obvious’ natural frequencies would have all kinds of bizarre consequences, not least that your AA could get cracked by a high card simply by virtue of the board pairing!
For the remainder of this article, we are going to focus our analysis on this more popular variant of Short Deck Poker, known as Triton Holdem. We move now to a discussion of the influence of the ante structure on proper strategic play.
Rather than the blind structure that we commonly associate with community card poker games, Short Deck Holdem uses a unique ante structure, which sees every player at the table post an ante, followed by a button straddle. The player to the left of the button, who I will refer to as #1 to avoid ambiguity, is the first person to act pre-flop.
This ante structure has a dramatic impact on the play of the game. In a 6-handed Short Deck game, the player in the #1 seat is being offered 7:1 on his pre-flop call. This compares extremely favourably with the 3:2 offered on a pre-flop call in a typical blind structure game. Open-limping goes from being the strategic pariah of the Full Deck game to an essential component of Short Deck strategy. Even players new to the game quickly learn that it is necessary to protect their limping hands against raises by including some very strong hands, such as AA,KK, or AK to limp-reraise.
The most important effect of this ante structure is to guarantee that Short Deck includes a large number of multiway pots, with a very diverse set of pre-flop scenarios, and hence plausible ranges, taking place in any given session. A blind structure game would be very susceptible to computational methods, and would quickly lose its lustre as experienced No Limit players could develop an edge using similar methods to the Full Deck game. With my team I have developed a suite of software tools to aid my research into the game, and the complexity inherent to multiway pots means that my skill in framing problems and using analytical methods is not overshadowed by the machine, but complemented by it.
It is easy to overlook another distinct feature of this ante structure, namely that whenever one opens with a raise one is forced to play out of position post-flop (this is why I chose to call the player first to act pre-flop #1, rather than UTG). This makes the position of every player other than the button far more disadvantageous than in the Full Deck game, and serves to increase the power of the button’s position proportionately. The only way to play in position post-flop from a seat other than the button is to isolate limpers. In theory, this factor should be a powerful suppressor on the frequency with which players enter the pot from early seats, despite the exceedingly favourable pot odds. However in practice, in almost any Short Deck game that you can find, live or online, most players at the table find those odds too sweet to pass up with even the weakest starting hands.
On that note, let’s wrap up this strategic analysis with a brief study of Short Deck Holdem starting hands.