EP and MP ranges are primarily concerned with strength and balance, so they can’t be easily attacked from LP both pre and post flop.
However, due to increased positional advantage, CO and BTN are best played exploitatively. This is achieved by using HUD extensively to identify opponents’ tendencies.
In this article I will cover CO position, next one will cover BTN.
CO is the second best position to open from since only 1 out of 3 remaining players (the BTN) has positional advantage against it.
This justifies wide opening ranges, but still not too crazy since BTN and blinds will pay attention and can 3-bet accordingly. However, by using HUD stats, it is possible to fairly easily maximize positional EV without ruining a tight solid image from EP and MP.
In general, before opening action a CO player looks at the following stats:
- BTN folding frequency against CO open (most important!)
- BTN calling frequency against CO open + fold to flop cbet
- BTN 3-bet frequency against CO open (+ fold to 4-bet)
- blinds folding frequency vs steals (most important!)
- blinds calling, squeezing, 3-bet frequencies against steals
In situations where there is a good chance opponents will not contest the pot, I open the entire following range:
This range contains 414 hand combinations (31.22% of all possible hands).
It has both decent card equity (considering the size of the range) and decent speculative value while being fairly easy to remember:
- all Aces (unsuited Aces contain blockers to opponents’ 3-bet ranges)
- all Broadways (unsuited have blockers + decent high card value)
- all pocket pairs
- all suited connectors from 54s up (max number of possible straights)
- all suited gappers from 64s up (max number of possible straights)
I would like to note against that the “real” RFI range visible in opponents’ HUDs will be smaller since in suboptimal situations (high chance of 3-bets / squeezes, high chance a sticky BTN player will call and fight for the pot post flop) we will not use the entire 31% range.
In those situations, we can use any MP opening range (mentioned in the “MP Ranges” article), preferably the 15% range. It can be supplemented by some unsuited Aces (blockers against 3-bets) against players who like to either 3-bet or fold.
This will reduce the apparent size of our CO range while maintaining decent exploitative EV.
Main danger is BTN 3-bets, which is why we need to look at the player’s tendencies before we open the pot. Our primary defense against 3-bets is the HUD!
If we used the HUD correctly, against conservative BTN players we will generally be able to freely fold all dominated hands (weak or unsuited Aces, unsuited Broadways) outright even if it is theoretically exploitable. This is possible because we normally automatically profit from stealing blinds against players who do not defend their BTN aggressively and therefore have no need to fight 3-bets with poor hands.
Against players who 3-bet wide and give up relatively easily post flop, we can simply open a tighter range than normal but then refuse to fold too much and fight back with calls as described in previous articles.
Against players who 3-bet wide and fold a lot to 4-bets, it is possible to use Ace-heavy opening ranges and simply 4-bet (and fold bluffs to shoves). Since I do not generally 4-bet much from EP and MP, it is hard for opponents to be really confident when facing aggression against their wide 3-bet range.
Against players who aggressively defend their BTN, do not fold to 4-bets too much and are tricky post flop, we can play as if we are in MP (conservative opening range but play it stubbornly). On regular tables, it is probably a good idea to simply leave the table since CO positional EV is important for overall profitability and taking a big hit there will hurt us too much.
3-bets from blinds can be handled by looking into their post flop tendencies and seeing if they can be exploited. If not, normally it is not a big deal to fold weaker (dominated) parts of our range since proper opening will be automatically profitable anyway.
Squeezes and 3-bets + cold 4-bets
Best way to avoid trouble like this is to use the HUD properly before opening the pot. This allows us to avoid excessive folding to aggression, which is the default reaction in most cases due to the weakness of our range and the problem with call – shove line from BTN (trapping blinds with premium hands).
We need to have data in our HUD about squeezers range and reaction to shoves (SQZ – fold) so we can profitably 4bet shove.
Against BTN call and squeeze from the blinds we 4-bet shove AK (blockers + good equity), QQ (CO open + BTN call are often weakish hands, so squeezes are often fairly weak hands themselves), KK, AA and possibly some suited wheel Aces (blockers, decent shove equity), but it depends on the HUD data. This traps the original BTN caller, who normally has to fold here (if he was trapping with KK+ we need to make a note).
Against a 3-bet from BTN and cold 4-bet from the blinds, we could be in a bad shape, but it is rarely a mistake to go all in with QQ/AK against normal ranges. In any case, this is a shove or fold decision.
Against both 3-bet and cold 4-bet from the blinds I would actually be slightly more inclined to fold just due to the difference in ranges, but as usual, in LP steal situations this is highly dependent on HUD / notes.
I generally do not 3-bet light from CO, since I find it more profitable to call in position (depending on probability of squeezes). I like flatting and shoving premiums (against squeezes), so after a while, people stop attacking flat calls.
It is best to 3-bet against a HJ (hi-jack) open since this position has slightly weaker ranges than earlier ones. We need to use positional RFI (“raise first in”) in our HUD and try to estimate the size of HJ range (usually slightly larger than RFI average for MP).
If we do decide to 3-bet, it is best to use a polarized range (either KK+ or AK/QQ+, balanced with wheel Aces as bluffs). This however, makes it harder to dissuade people from attacking our calling range (we can only have so many premiums).
Ideal situation for light 3-bets is:
- original raiser has a wide range and/or folds too much to 3-bets
- original raiser likes to call a 3-bet but then check-folds the flop too much
- players still to act are very unlikely to flat call a 3-bet or make a cold 4-bet
- we normally have a tight 3-bet range and in general, our image is very solid ( = our exploitative play does not provoke people to go wild)
I generally use the same criteria as in MP to decide whether to flat call:
- position of the raiser (EP or MP)
- size of his range (if we have HUD data for his positional RFI)
- post flop habits (does he barrel or give up easily), which influence our ability to take the pot even when we miss
- probability of a squeeze (normally slightly larger than in MP since our perceived calling range is wider here)
Normal default calling range in CO is between 7% and 12% of hands (as detailed in previous articles “EP Ranges” and “MP Ranges – part 2”).
Our call – shove range is slightly larger here than in MP so we can expand the calling range slightly. In ideal conditions, maximum range I would use is 15% of hands:
This range contains 198 hand combinations. Our actual range (visible in opponents’ HUDs) will be smaller due to open folding weaker hands from the range in situations when squeezes are very likely.