I haven't written about theory since the isurapoker days, but here goes...Getting checkraised on the flop with an overpair on a coordinated board is a common tough situation. Many players have default plays based on experience and maybe a little bit of analysis. But it is instructive to sometimes dig a little deeper to analyze the core difficulties and options in the hand. A hand I recently played illustrates this.

I open from the cutoff and see a flop against the unknown big blind. Stacks are the 120bb, I have QQ, and the flop is 986 rainbow. The game is short handed 2/4. I bet 6bb into the 8bb pot, and get checkraised to 15bb. As a default, I would give my opponent a range of 66-TT, JT, 97s, 87s, 76s, 98s, 86s, A7s, some pure bluffs. The pure bluffs may be 22 or KQ for example. Today I will just analyze the option of 3-betting small and calling an allin. The more interesting options are calling and doing things on various turn cards, but I'll deal with those in the future.

Assume that everything but the pure bluffs will shove over my flop 3-bet. Against that range QQ has a nice edge with 55% equity. I am risking 110bb to win 130bb, so the break even equity is about 46%. Also, assume that villain bluffs the flop 15% of the time. Recall that we win 29bb when he folds, so the EV equation works out to:

EV 3-bet and call = (.15)(29) + (.85)[(.55)(130) - (.45)(110)] = 23bb.

That is a very nice profit, especially considering that 3-betting the flop is the easiest way to play the hand. Incidentally, we gain only 1bb by having villain checkraise and fold the flop (verify).

Of course we sometimes have marginal hands like A9 (41% equity) in this spot. With the A9 we are short of the required 46% needed to play for stacks (assuming no fold equity). Most players will be checkraising and folding the flop in this spot, so the 46% number needed to be adjusted based on that. The simple formula for this (verify!) is:

Adjusted equity = [(Amount lose) - (EV without showdown)] / (Amount win + Amount lose).

In our example, (Amount lose) = 110, (Amount win) = 130, and (EV without showdown) = 29bb * .15 = 4.3bb. Thus, we actually only need 44% equity to play for stacks in this example. What hands would you want to 3-bet shove with in this spot, and why? What other factors should be consider when deciding between a small or allin 3-bet?