thats the power of the button, you cant really do to too much against it. yes you will get a better price to call but you still end up oop and you will usually get punished for it :)

at first i would color code the regs that do these smallish position 3bets to spot them quickly. then i would try figure out their tendencies, like how they react to a 2x instead of 3x open in these co vs btn spots. (will they adjust their 3bet sizing to your 2x open or will they still 3bet to 7.5bb) if they lower their size you can defend easier and then figure out their postflop tendencies (like do they bet once and give up when called or do they tend to barrel allot and give you a hard time playing oop)

also if stats ("3bet btn vs co open") tell you that they simply use these small 3bets to steal very wide, you could adjust by 4bet bluffing a little bit wider. if they 3bet to 7.5bb make it 16.5bb which makes it awkward for the btn to fight back. he cant really jam because the pot is to small and he cant really 5bet bluff you because he would basically be pot committed (when playing 100bb effective) and he probably wont call your 4bet superwide either. (choosing that size your 4bet need to succeed ~58% to break even)

As a default, i take a 4bet/fold strategy until i have clear player reads that allow me to play OOP postflop.

I really don´t fold against those 3bets, especially if I´m not dominated most of the time (stuff like Kxs or Qxs) Axs I guess it´s a big deal because we have 30% against high PPs.

Don´t be afraid about peeling with such great odds. If you are open/fold to 3bet you are already -300bb/100. If you start peel those small 3bets and after a lot of hands have something like -250bb/100 you are doing better than fold.

About Stealth strategy about 4bet small I kind of disaggre. The same applies to him about call, and he have position, so If we 4bet very small we are offering very good odds. I would make 17.5bb/100 OOP. Against me for example I would peel 16.5bb VERY WIDE and 17.5bb not so much. And I´m a donkey in the field. Certainily there are better players than me who knows that.

Make a note of the ppl using that strat and adjust you opening range when you are in the co-btn spot with them.
The small 4bet makes use more inclined to call, we can call w 99-JJ, good suited broadways.

thanks,guys

 in my opinion , if in that situation : i m in the cutoff, button player knows nothing about my playstyel, and  sb or bb sits a big fish or regfish, that s  a good opportunity to open a little wider, isolating and playing pots with them in  position and have initiative. so in that situation i may open as wide as 35%-40%,i once played hu and do not fear known-3bettor while have position with that tight range(: .

If the situation: i m in the cutoff, button player is competent and knows me well, and there r no known big fish or regfish, i know how to open  co  as narrow as 17%-22%

so that s the dillema: i want to attack the weak player, and someone unknown attacked me, i m new to zoom (cuz it s time-consuming for selecting normal-table) and even i do not know myself well so i do not think those opponent got my style by data-mining, it seems more like a tendency: (

all i have to consider is how to play in the vaccum

i tried to adjust my range-- add more hands feel comfortable while calling gayish 3bet oop, feel comfortable while my 4bet got called ip and with some blocker to 4bet bluff with , should i remove some offsuited hands plays poorly in the situation like jto, qto, kto, k9o ,a8o ,a9o(which means a lot), and add a lot of suited Qxs Kxs hand and suited two gapper?

Don't think there is anything wrong with play OOP against these initiave junkies. Most of them go crazy when you start 4-betting a lot.

As long as your hand selection is good and you believe you have a post-flop edge, just take your odds and try to outplay them.

The more you get into pre-flop wars, the less room to use your skill edge.

Well your CO range should tighten versus good, aggressive 3bettors OTB. do widen your range when the players are overly-tight in the blinds or play very weak passive postflop, but don't get carried away. You can easily give bets back when you value bet too thin or push marginal draws when your range is so wide preflop -> postflop. 

If they risking 7 to win 4.5, you will need to defend more of your opening range, but not much more. Have a look at your range and see what hands you don't need to play. 

Depending on your opening range TT/JJ/AQ might be in your value get in range preflop. So that would leave 99-77, and your BWs hands. Maybe some Axx that can make a wheel. 

Its those offsuit broadway that widen your range and play poorly postflop. KQo is a solid hand versus those light 3bets but the others can get you into trouble.

Do have some player reads though. I rarely play postflop without some idea of how villain plays