# Blind Defence in BB vs BU minraise

• Black
Joined: 27.11.2008
http://forumserver.twoplustwo.com/56/medium-stakes-pl-nl/blind-defence-bb-vs-bu-question-1271250/#post35913862

I started a thread in 2p2. Hope to have the same discussion here and hear more opinions.

When you watch any high stakes HU match, you'll see that the BB defends like 80%+ vs a SB min-raise (What i mean by defend is both calling and 3betting). Obviously they must be doing something right with all their math calculations.

I'm wondering how that applies to us at midstakes. Assume both players are equally skilled and fairly good mid-stakes players with good balance, and BU raises to 2BB. BU has really balanced frequencies, Flop Turn River Cbet are 65/50/50.

How wide should we defend vs a

1) 50% range
2) 60% range
3) 70% range
4) 80% range

Using the High Stakes HU match as an example, BB is defending approximately defending 80-85% of SB's opening range. So I'm wondering if we should use a similar "formula" to roughly dictate our defence range.

Traditional old school theory says that because we are OOP and without the initiative with a capped range, we should defend way tighter (maybe 50% of opening range?). But these days people just place so much more emphasis on folding less, and being committed pre-flop due to pot odds.

I tried defending more hands, calling like 40%-50% of hands in BB with a lot of crappy hands like Q2o. But I found that my Flop Fold to Cbet started increasing to 50% due to the really poor playability of many of those hands which basically meant that I was just burning money post-flop.

Thoughts?
• 5 replies
• Bronze
Joined: 09.07.2010
In theory, given the same opening range we should defend more in 6max because of the added dead money (sb).

The thing is, while multitabling may be a good idea to just fold the worse 30-40% of the hands because the EV of calling with them is not that good anyway, and you put on yourself on difficult postflop situations.

Highstakes HU matches are different because they need every bit of EV in order to have an edge.
• Bronze
Joined: 09.07.2010
lnternet, IFS...any thoughts?
• Bronze
Joined: 22.11.2008
lnternet, IFS...any thoughts?
• Global
Joined: 23.11.2009
my tl;dr answer is "i don't know, but i think i know how to find out."

In a vacuum you can decide how often to defend by taking your average investment when you lose divided by the average pot size when you win. The output we get is the minimum equity required to play for value given some assumptions.

Accounting for the rake is simple, just decrease the pot we expect to win. Accounting for position is trickier. I've estimated the effect of position in fixed limit games but not NL.

In heads up pots, the amount we lose when we lose is well defined. its roughly half the average pot given that we lost. The average pot size given that we've won is something we can look up in our database. Looking at pots this way will probably go a long way to accounting for the effect of position but you'll need some massive databases.

This kind of approach is the one I've used in Fixed limit HE. There, the average pot sizes are small. As a result, the blinds contribute a lot to the final pot size. We end up defending about half the time vs a 50% BTN range.

In No-limit, I expect the situation will change. If the pot size relative to the blinds is big, if the effect of position is large, and once we factor in the rake its certainly possible that we might arrive at required equity vs range >50%.

edit: Worth mentioning that HU/HU is different than 3 handed+ because playing the BU open raiser HU in one case means there's a small blind of dead money contributed.
• Bronze
Joined: 19.06.2012
The best I can offer is you try out a super loose strategy and then filter your database to get a winrate approximation for hand groups and see for which hands calling outperforms folding.

Start by looking at winrates of your worst defense hands right now. If those are significantly over -100bb/100 you can likely call more.

I could tell you what I believe to be good ranges, but that would be nothing more than guessing / experience, which you shouldn't trust much. This would also overlap a lot with 3bet range construction. Read sensitivity is also important, which is tough to describe in a few sentences.