Semi-Bluff Sequences – Attacking the weak Spots [Beta]
Introduction
In this Article
- Semi bluffing on the highest level
- The real costs of a semi-bluff
- Semi-bluff sequences
This article deals with semi-bluffing on the highest
level.
Traditionally, a semi-bluff is a bet or a raise with a
currently marginal hand which has outs, in a situation in
which it is possible that every opponent will fold.
This
definition is too restrictive though and isn't enough to master the
semi-bluffing.
Extended Definition of the Semi-Bluff
A semi-bluff is a betting sequence which can span flop, turn
and river, with a hand which is probably not ahead for now, but
has outs.
This definition makes it clear that the action
with Hold'em on the different streets is all tied together. A turn bet
after a flop check-raise has a much higher fold equity than a turn
donk bet after a flop call.
The real Costs of a Semi-Bluff
A semi-bluff costs less than a pure bluff. The reason for
this is that in many cases you get back the bets you make as
semi-bluffs if you hit your outs.
The real costs C of a
semi-bluff result from the size of the bet B, the amount of expected
callers + yourself N and the chance to hit one of your (discounted)
outs P
C = B*(1 - N*P)
Now keep in mind the following:
If we make a semi-bluff bet on the flop with a flush draw, we are
sure to get to the river one way or another. Thus in this case, the
chance P to hit a flush card until the river is 35%. But in cases in
which we plan to only spend the semi-bluff on the flop, our chance P
can only have the probability of hitting an out when the turn card is
dealt.
An example: Let's say we are heads-up at the flop
against 1 opponent. We bet a flush draw as semi-bluff and plan to
take it to the river. That means:
C = 1*(1 - 2*0,35) = 0,3
If we now bet into our opponent, how large is the chance that
he raises? Let's call this chance R. If the opponent raises, the
costs for our semi-bluff double up.
Thus our real costs are:
C* = 0,3 + R*0,3
Let's now say that the pot on the flop has 4
SBs. Simplified, our semi-bluff is +EV if it gets the opponent to
fold in (0,3 + R*0,3) / 4 % of the cases.
Let's assume our
opponent is a TAG and raises here in 20% of the cases. Then our
semi-bluff is +EV when he folds after our bet in 0,36/4, so a bit
more than 9% of the cases. Let's assume our opponent is a LAG and
raises in 50% of the cases. Then we would need a fold equity of at
least 0.45/4 = 11.25% – which is still very little.
Here we
can already note down our first interim findings: With strong
draws you should still semi-bluff even against LAGs.
Semi-Bluff Sequences
The advanced players amongst you have certainly asked themselves
the following in many cases: Imagine that you are first-in on the
button and want to steal the blinds. The SB folds, the BB makes a
3-bet. On the flop the BB bets again into you. You now have a hand
with some outs and would like to semi-bluff. The question now is:
call flop, bet/raise turn or rather raise flop, bet turn?
This
problem can be solved methodically. First of all, you roughly
calculate the costs of both sequences. Let's say we have a
flush draw like in the previous example.
A bet on the flop
then only costs us 0.3 SB effectively. If the flush doesn't hit on
the turn, our equity decreases to about 20%, thus a bet on the turn
costs 0.6 BB. However the flush could hit on the turn in 20% of the
cases, so that we can subtract 20% from the 0.6 BB, so that a turn
bet (seen from the flop) only costs 0.48 BB in effect.
Let's
assume that our opponent always bets the turn as well even after a
flop bet. Furthermore, there is the risk R that our opponent
re-raises if the flush doesn't hit on the turn.
The costs for
call flop, raise turn are thus: 0,3 SB + (2 - PNB)*0,48 BB +
R*0,48
PNB designates the chance that the opponent bets the
flop, but only checks on the turn.
The costs for raise flop,
bet turn are thus: 0,6 SB + (1-FF)(0,48 BB) + R' = 0,3 + (1-FF)(0,48)
+ R'
R' designates the extra costs which occur when the
opponent raises the turn or 3-bets the flop. To calculate them
exactly would be tough though as we might eventually give up our
semi-bluff in case of a flop 3-bet. FF designates the chance that our
opponent already folds on the flop.
With a high probability,
R' < R*0,6 BB though, as a turn 3-bet after call flop, raise turn
happens considerably less often than a flop 3-bet after raise flop,
or a turn check-raise after raise flop, bet turn. On the other side,
there are cases in which the opponent already folds the flop and thus
no extra costs can occur on the turn. Thus the following exception
makes sense: R*0,6 = R'
Therefore, we can roughly say the
following:
Costs for call flop, raise turn = 0,15 + (2 -
PNB)*0,48 + R'
Costs for raise flop, bet turn = 0,3 + (1-FF)(0,48)
+ R'
Cost-Benefit Deliberation
Now we have to compare the costs of the betting sequences with
their generated fold equity. This is extremely dependant on
the opponents and the board.
Some of you might remember Onkel
Hotte's coaching session in which he played against an opponent
called Baller6969. This player was extremely tight, but certainly
aggressive. The chance FF that he would fold against a flop raise
probably lay at about 50%. The chance that he would bet again after a
flop bet was very high, let's say 90%, so that PNB = 10%.
This results in:
Costs for call flop, raise turn = 0,15 + 1,9*0,48 + R' ~=
0,9 + R'
Costs for raise flop, bet turn = 0,3 + 0,5*0,48 + R' ~=
0,54 + R'
With this opponent, we notice the following effect:
Even though we bet 2.5 BB with call flop, raise turn, and 2 BB with
raise flop, bet turn, the “effective costs” are considerably
lower. Actually, raise flop, bet turn costs about 40% less than call
flop, raise turn. Against Baller6969 we had no proportionally higher
fold equity with call flop, raise turn. Thus against this opponent,
raise flop, bet turn is the better choice.
How come? The flop
is Baller6969's so-called weak spot.
A weak spot is the earliest possible
situation in a hand in which a player has a significant fold equity
for the first time.
With many opponents on the mid limits (20/40, 30/60), this weak
spot is definitely at the turn. In heads-up, most players use the
raise flop, bet turn betting sequence with hands like Ace high, while
they very often fold against call flop, raise turn.
This can
also be mirrored in the previous equations. Let's say an opponent has
a FF value of 10% and a TNB value of 10% in the previous equation.
This would be typical for a 20/40 semi-LAG. This ensues:
Costs
for call flop, raise turn = 0,15 + 1,9*0,48 + R' ~= 0,9 + R'
Costs
for raise flop, bet turn = 0,3 + 0,9*0,48 + R' ~= 0,73 + R'
Now
call flop, raise turn only costs 12% more than raise flop, bet turn.
Against this opponent type we assume that our fold equity with call
flop, raise turn is about 50% higher than with raise flop, bet turn.
This opponent type will only weaken with turn raises. Against turn
raises he has his weak spot.
Is there more to this? Are there also opponents who don't have a weak spot? Yes,
and quite often, in fact. These are the so-called maniacs who 3-bet
the turn with very little or nothing at all. Such players extremely
weaken the cost-benefit calculation with a semi-bluff. Let's take a
mathematically borderline case: An opponent who only bets and raises.
Against such an opponent, you have a fold equity of 0. A semi-bluff
with a flush draw without high card value is thus a guaranteed losing
play. In general, against such a maniac you play your flush draw with
a simple call flop, call turn, fold river (in case you don't hit) in every case.
There are also opponent types (very LAG, but able to
fold) and situations, in which you shouldn't wait for the river with
your raise. These situations are extremely rare though.
This
also explains the principle that the more LAG your opponent is, the
less you should semi-bluff; and if you do semi-bluff, you should have
a strong draw.
The weak spot of an opponent isn't really
constant though. There are boards which are so scary that also a
LAG often folds against a flop raise. On the other hand, there are
boards which look so harmless that even weak-tight players won't pay
any heed to your flop raise. You have to keep this in mind while
considering your decision.
The general Semi-Bluff Principle
Step 1: Estimating the costs for a semi-bluff sequence depending
on your outs, the board and the opponent type.
Step 2:
Estimating the advantage of a semi-bluff sequence, this means
estimating the fold equity.
Step 3: The choice of the
semi-bluff sequence in accordance to Steps 1 and 2.
Rule
of thumb: Find the weak spot of the opponent and place your bet
there. Keep in mind that the weak spot is the earliest
possible spot in a hand in which your opponent offers a
significant fold equity.
Also keep in mind: With special boards, the
weak spot can shift.