3bet MDFs Question

SliverOverlordSliverOverlord Red Chipper Posts: 323 ✭✭✭
I've been going deep into my 3bet game recently and I came across a spot that confused me. I believe I have an answer but I'd love any addition feedback, whether it be something I overlooked or confirmation on my hypothesis.

Looking at Minimum Defense Frequencies when facing a 3bet, I quite an odd spot. I have a slightly looser than TAG open range for UTG, about 128 Combos (the exact range doesn't matter in this example), opening to 2.5bb. I face a 3bet to 20bb I need 72.9% equity to call, but I need to be defending 21 combos of the original 128. By the equation for MDF, I need to be defending QQ+AKs, but even against a Maniac 3betting range of top 13% of hands, QQ and AKs don't have the required equity for this to be a profitable call, based on the pot odds given.

My solution/adjustment, I can only open enough hands such that KK+ is the dependable 16% of my range.

One reason I am confused by this, if villain is only 3betting QQ+AKs, why do MDFs go out the window? And why wouldn't having a mixed strategy using this huge 3bet size just print money in the long run as long as villain was correctly adjusting his range? Especially when you take into consideration the guessing game and tilting people through these huge sizings.

This may be me just confused or overthinking it after a long day of work, poker, and poker study, but any input/clarity/confirmation/solutions to this would be much appreciated.


  • The MuleThe Mule Red Chipper Posts: 790 ✭✭✭
    @SliverOverlord , I was discussing a very similar question with some other Red Chippers last week.

    MDF is the (unexploitable) defending frequency required to prevent your opponent being able to bluff with a2c.

    Your equity calculation is based on the (exploitative) assumption your opponent is 3-betting a value only range.

    These are not consistent - either your opponent is 3-betting a very strong range and you can only continue with very strong equity hands, or your opponent may be bluffing so you need to defend at the MDF.
  • Adam WheelerAdam Wheeler Red Chipper Posts: 2,659 ✭✭✭✭
    What are you talking about when you say you need 79%?

    Pot is 1.5BB
    You open for 2.5BB (Pot is 4BB)
    V 3B 20BB (Pot is 24BB)

    Pot odds = 17.5BB (Your call 20BB-2.5BB)/4BB+20BB+17.5BB) = 42%

    MDF = 4BB/4BB+20BB = ~17%
  • Duncan TDuncan T Red Chipper Posts: 55 ✭✭
    Without trying to further murk the waters of GTO MDF vs exploitative ranges..

    Once you calculate your pot odds correctly (thanks @Adam Wheeler for beating me to it!) even if V is only raising value hands your QQ+, AKs is doing fine until his range tightens up to KK+. As such your MDF range is still in decent shape against unbalanced 3B ranges most of the time.

    So really, in practice it comes down to reads on villain in play. When facing a 3B to this size is V the type to only do this with KK+?

    For me, MDF etc and other off table range building is more of a baseline for default lines. These can then be adjusted based on game dynamics / V tendencies etc.
  • SliverOverlordSliverOverlord Red Chipper Posts: 323 ✭✭✭
    Thanks @Adam Wheeler. Something seemed off when I saw the 72.9% equity but I didn't think it through full. Always helps when my excel spreadsheet formulas are actually correct!

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