Why is the BB always expected to call a short stack?

[TheCrazyHatLady]

Late in the tournament (9 hours). Field of 159, 12 players left, everyone is in the money at least $250 cash, however top 10 win a seat worth $1800 in a $500,000 guaranteed tournament and $400 cash.

6 players at the table. BB $6000, SB $3000, BTN ante of $6000, short stack CO goes all in for $14,000. Everyone folds to me the BB, I have about 20 BB, I show an Q7o saying "I wish I could call you." The gentlemen at the table freak out (nicely), "You had to call!" "I would have called, would you have called?" "In a heart beat". The most boisterous were table chip leaders with 30BB or more.

This was one of 2 final tables, we had been playing together for about an hour. The short stack all in player had only tabled 3 hands, they were all solid winners. I figured him for at least Ax, probably better. I figured I was behind and it just wasn't worth risking my chips. It seems to be common thinking
that any 2 cards against an all in short stack, if BB are a go, I just don't see it.

So, I did the math to try to show myself why I was wrong.
Pot odds: Blinds and ante put 15BB in the pot, Short stack puts in 14BB, it costs me 8BB. Using the easy percentage method 8/27 = 29%
Equity using rule of 2 and 4. Have maximum of 6 outs, probably less if he is suited. Short stack is all in so 6 x 4 = 24%.
My equity is less than my pot odds, based on this my fold was correct.

Am I doing the calculation wrong? If not, why does everyone assume you must call with any two cards?

[kkep]

You don't have to call but I think you should. You are only risking an additional 1.5 blinds.


I'm assuming 6 handed.

The CO open shoves 2.5BB so lets say idk 60% probably wider tho
vs that range you have 44% equity

The pot is 29000 you have to call 8000 more. you need 28% or so to break even.

That's a pretty great spot to try and pick up a pot equal to about 25% of your stack

Technically in that exact spot you are suppose to call with 100% of your hands. Even 27o has 27% equity

[LondonImp]

So pokerlisting have got their calculation explanation wrong? I wonder just how many people have based their learning off of that, pretty horrendous really.

[kkep]

Probably why I have been so confused! I chose their formula bc it had one less step and without thinking about it I assumed the results were the same. Math isn't my strong suit to say the least!

[reeeeeeper]

LondonImp @kkep

bet / (bet + pot) == pot odds
pot / (bet + pot) == minimum defense frequency (just for kicks, not relevant here)

What is relevant, let's say you were offered a game to flip coins where you and your opponent each put up $5 and heads you win, tails he wins, then this works out.

Your $5 / (Your $5 + His $5) == 50%, a break-even game since it's the same as the odds of getting heads.

If you calculated the pot odds your way...

Your $5 / His $5 == 100%

...this is obviously not right. You would be burning money. You have to include your bet in the value of the reward when you win. The same applies to poker, it's just that the numbers aren't as simple so it's not as clear.

[Guido]

No brainer call , vs any reasonable range you will have 29% equity

the rule of 2 and 4 is for calculating pot odds Beginning from Flop

here you are in a preflop Spot

As a rule of thumb getting 2:1 on a Call you Need a reason not to call (for instance Satellite play) here you are getting even better odds

you have to close your eyes and call here

and believe me it is that much Fun to suck people out in this any 2 spots

[reeeeeeper]

You're being laid 3.5:1. If his range is all AX and pairs 77+ like you think (and it's almost certainly a lot wider than that) you're a 2:1 dog. Easy call.

[jjpregler]

In spots like this, I might call before even looking at my cards. Because if I see what I have I might talk myself out of an easy call.

You have to call 8k to win 29k. Your pot odds are 3.6:1. Your break even equity required is 21.7%. Even if you pad that with 5% extra equity as an edge, you need 27% to call.

http://www.pokerstrategy.com

CO 71.32% { 22+, A2s+, KTs+, QTs+, JTs, A2o+, KTo+, QTo+, JTo }
BB 28.68% { 72o }

And you never use the rule of 2 and 4 for preflop. That is a post flop short cut.

[RealJPB]

To simplify the what others have already broken out, the big blind doesn’t ALWAYS have to call the short stack. But when it’s only an additional 1.5 big blinds you have to call no matter what cards you have.

[drs13]

Why doesn't the float the turn show that BB is suppossed to call in this stiuation?

[kkep]

drs13 We need to set it up for our position. You are misunderstanding it.

[drs13]

I misspoke. You set it up for your position, but my point remains...on the FTT app there is no direction for the Big blind to call.....anything at all for this specific scenario.

[kkep]

drs13 keeping playing around with it......Call an all-in from Big Blind for 2 effective big blinds against:

- UTG with 100.0% 22+, A2s+, A2o+, K2s+, K2o+, Q2s+, Q2o+, J2s+, J2o+, T2s+, T2o+, 92s+, 92o+, 82s+, 82o+, 72s+, 72o+, 62s+, 62o+, 52s+, 52o+, 42s+, 42o+, 32s, 32o
- Hijack with 100.0% 22+, A2s+, A2o+, K2s+, K2o+, Q2s+, Q2o+, J2s+, J2o+, T2s+, T2o+, 92s+, 92o+, 82s+, 82o+, 72s+, 72o+, 62s+, 62o+, 52s+, 52o+, 42s+, 42o+, 32s, 32o
- Cutoff with 100.0% 22+, A2s+, A2o+, K2s+, K2o+, Q2s+, Q2o+, J2s+, J2o+, T2s+, T2o+, 92s+, 92o+, 82s+, 82o+, 72s+, 72o+, 62s+, 62o+, 52s+, 52o+, 42s+, 42o+, 32s, 32o
- Button with 100.0% 22+, A2s+, A2o+, K2s+, K2o+, Q2s+, Q2o+, J2s+, J2o+, T2s+, T2o+, 92s+, 92o+, 82s+, 82o+, 72s+, 72o+, 62s+, 62o+, 52s+, 52o+, 42s+, 42o+, 32s, 32o
- Small Blind with 100.0% 22+, A2s+, A2o+, K2s+, K2o+, Q2s+, Q2o+, J2s+, J2o+, T2s+, T2o+, 92s+, 92o+, 82s+, 82o+, 72s+, 72o+, 62s+, 62o+, 52s+, 52o+, 42s+, 42o+, 32s, 32o