Let's say that we are playing an mtt full ring with 10% antes and 25bbs effective and there are no icm considerations.

We open 2bb in mp and button 3bets to 6bbs, its folded back to us, whats our thinking here? as opossed to 100bb deep we would could call with most of our range because we have the right odds and often realize enough equity to make it profitable. Short stack however, I've seen a lot of good players fold a lot and I'm confused of why that is, what is the logic or mathematical backing to this?

Part of good MTT play is having a good idea of what you will do with each stack size before you do it.

Usually if people raise/fold off 25bb it's because they were stealing or raising with a hand that doesn't play well out of position and won't have good implied odds due to the effective stack size.

But what dictates what I call with and what I go all in with? Because I'm pretty sure I could call the 3bet with QJs and also profitably shove it.

That's obviously very villain-dependent. But certain hands flop better than others so they generally play better as calls than 4-bets. QJs is one example. But with a hand like A5o for example you're generally better off playing it as a 4b or fold, depending on villain tendencies and such.

Makes sense. Thanks.

How do you establish that QJs is infact more profitable as a call as opposed to a shove? That's basically the core question to this topic.

You can't really. You can calculate the ev for shoving based on villain's 4b-call range but you can't calculate the ev for calling because there are too many postflop variables.

But the point is, when you have a hand that flops as well as QJs there is no reason to ever turn it into a 4b-bluff because that's what you're doing when you decide to 4b-shove. You're risking your 25bb to pick up 9.5bb, which is a good % of your stack, but there's no reason to take that risk when you have a hand that flops well and gives you lots of ways to win a bigger pot postflop without risking your tourney life.

With a hand like A5, however, it doesn't flop nearly as well and risks being dominated by a better Ace, so you don't really want to call and see a flop with that hand out of position. 4b-shoving is a big risk but against the right opponent it can actually be the right play compared to folding or calling.

Thank you, I think that I've got the hang of it now. Really appreciate the help!!

1) adjust your preflop opens accordingly - open less with smaller stack obv in most of the cases.

2) 20-25bb is much better to play on the more aggresive side oop (4b shove more) since if we flat much we will be in too many nasty flop spots when we face a cbet. obv as darthmaul said everything is very player dependant. try HRC/icmizer and do a lot of spots with different villain 3b ranges. start with what is villain 3b calling with and add reosanble bluffs and see how what performs vs that.

Do you think its ok to have a 4b or fold type strategy?

i guess it's only option with 25bb and less oop except in some specific situations

I would agree. Calling would be limited to the small number of suited connectors that have too much value to fold but get crushed if called when shoved (QJs/QTs/JTs stuff).

But if we are only calling suited connectors how do we stay balanced? I mean we can't really have nutted preflop hands...

I would throw in some calls with big hands too. You open, get 3b, call, check flop to Villain, he bets, you shove. Sometimes you have QJs/JTs and x/shove a draw or whatever, sometimes you have a big pair.

When we are choosing our "value 4betting range" does that mean when we shove and get called by the 3bettor our value range should have a minimum of 50% equity?

no. i ll try to break it down so you can do it on your own ( disclaimer: im not 100% sure about this as I use HRC/icmizer for these calcs )

so we have 25bb stack and we open TT to 2bb. Pot with antes was already 2bb and we face a 6bb 3bet. so pot is 10bb.

when we shove he folds 55% of the time ( example ) , and he calls 45% of the time. our TT has 40% equity vs his calling range (TT+ AQs+ AQo+)

I think complete math is :

0.55 * 10bb ( when he folds to a 4b shove )
+
0.45 * ( 0.40 * 52bb ) (when he calls and we win )
-
0.45 * (0.60 * 52bb ) (when he calls and we lose)
= 5.5 + 9.36 - 14.04 = + 0.82bb

Somebody correct me if I'm wrong which is huge possibility

When the 3-bettor in ur case is 3-betting to 6bb with (TT+ AQs+ AQo+) +( some bluffs) and get shoved on he is obviously calling with his value range (TT+ AQs+ AQo+) and folding his bluffing range, but my question is what dictates that these hands are indeed value hands?