Big O

Why the fifth card changes everything

Five hole cards give ten two-card combinations instead of six. Every player therefore arrives at the flop with more draws, more made hands and more redraws, and the practical consequence is that the hands which win pots get stronger across the board. A nut low that would be unassailable in Omaha hi-lo is routinely shared in Big O; the straight that would be the nuts is beaten by a flush; the flush loses to a full house.

The scoop problem

In any split-pot game the money is in scooping — taking both halves. Big O makes that harder in two ways at once. The low side is crowded, because A-2 is held so often that being quartered is normal rather than unlucky. And the high side needs more than it used to: two pair and weak straights are rarely good at showdown in a multiway pot.

The practical discipline is to fold hands that can only win half. A one-way low is a losing holding; what you want is a hand with low potential and genuine high potential in the same five cards.

Betting formats

It is most often dealt pot-limit, where a pot-sized bet into a multiway field quickly commits stacks, but limit and no-limit versions both exist. The format matters more here than in most games, because the number of live draws in a five-card game means a pot-limit Big O pot can be raised very large while several opponents still hold correct calls.

Where to find it

Big O is a card-room game that grew up in the American South and West and has travelled with the cash-game circuit — it is a staple of Texas and Californian card houses, and turns up in dealer's choice rotations and in mixed-game festival side events. It is far more common as a cash game than as a tournament.