News: When is it right to open shove flop?

This week Barry Carter looks at flops where it is sometimes correct to open shove for two times the pot (or more).

In the self study series Barry Carter shows you how he tried to solve a poker problem then consults a coach or solver to get feedback on his method.

I recently played a hand, at one of the best online poker sites, where I had KK on a Jack high board and the solver told me, surprisingly, to shove flop for 3x the pot. It felt like a big waste of a hand like KK, so I was determined to learn why, and what situations we should do this in.

Once again using my favourite feature of GTO Wizard, the aggregate reports, it was easy to identify the spots to do it in. I tried at a variety of stack depths and scenarios, the one below is BTN vs SB, 3-bet pot, with 60BBs effective. I filtered for hands where there was a lot of shoving on the flop as the first action, in this instance a shove was 2.5 times the pot, and it was clear the right sort of boards to do it:

You can't see all of them, but it was always boards with a flush draw and two connected cards between a Q and a 9. Spots where it was possible for a lot of broadway hands to make a straight and/or a flush on the turn. Rarely would you see this on low-connected boards with a flush draw.

To dig further, let's look at the J♦T♥6♥ board where it happens the most, 24.2% of the time. This is the SB betting range, with the darkest red hands being the shoves:

The really strong hands like sets elect to check behind. It is always strong but vulnerable hands, like KK, QQ and AJ that shoved. These are hands that could quickly shrink in value if a third heart or a connected card comes, not to mention an Ace. Perhaps crucially, if your hand improves it might bring the other guy a straight. You are not loving life with KK if the turn brings the K♥.

This is what we call a dynamic board in poker, similar to a wet board, where a lot of turn cards can change the fortunes of the players. To get more insight, this is what the BTN does when the SB does shove:

First of all, a lot of hands that don't beat top pair top kicker call, so that is good for our value. This is because we had the right mix of bluffs and value in the shove range (The bluffs are high straight draws with flush draws, hands like K♥Q♥ and A♥Q♥). Secondly, we get a lot of hands we would hate to give a free card to to fold. This is mostly weak straight draws like AQ, KQ, Q9, Q8, 98, 97 and 87.

I also used the node locking feature in GTO Wizard to see what happens when we force the SB not to shove and use the smaller bet sizes instead. This is what happens, for example, when the SB bets 33% pot:

The BTN continues with more hands and can raise a lot of them. They raise all the good value hands and bluff with the gutshot-type hands we made fold previously. We get put in a more uncomfortable position and we let in hands that have equity against us. On average the SB makes 11.33BBs in GTO World, but in this node-locked example, they only make 11.06BBs. That may not sound much, but not shoving is a 27 BB/100 error long-term.

A practical way to sum up the situation is that on connected broadway flops with a flush draw, the preflop aggressor is often ahead, but the defender hits the board a lot. There are a lot of bad turn cards for the preflop aggressor, including ones that turn their made hand into two pair or a set. The way to get value from the many one pair hands that will call while pricing out the weak draws that have equity is to shove the flop.

Previous self study articles

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