Bet sizes give off information, and you can use the information
given off by the size of someone’s bet to help read their hand. Say someone min‐raises pre‐flop to open up the betting. What does their bet size mean? It means they have a hand that they want to see a
flop with but it’s not good enough to raise a large amount or play a big pot pre‐flop with. They don’t limp because they don’t want to have to call a raise behind them. Basically what it means is they are trying to see the flop as cheaply as possible. This can be a good spot to auto‐raise with any two cards (this can’t be done every time though or your opponent will know something is up and play back at you). It takes time and experience and it’s a continual process of refining how to change gears and how often these plays can be done.
For example consider a hand of HU $2/4 where the opponent raises on the button and I call with 6‐7s. The flop is K‐Q‐6, I check and he checks. The turn is a Qo, I check and he bets $12. If he had a king he would have bet the flop or probably checked the turn again to trap. Or he would bet more on the turn because his king should get him more value than half the pot and more value will probably be ob‐ tained by betting full pot or by checking behind to be tricky. If it’s a queen he would want to build a big pot so he’d bet more money.
As it is, it looks like he has a mediocre to weak hand or is bluffing. The question is whether to call or raise? A good thinking opponent who has say 9‐9 could call a check‐raise because they know they in‐ duced it by acting weak and it is difficult to put me on a hand. And would a king check/raise the turn like that? A king would probably lead the turn or check‐call, since check‐raising is a strong line for it.
Of course I’d definitely play a queen like that but trips are hard to come by and it’s either trips or a semi‐bluff of some sort. However this opponent was weak and if I call then I face the disadvantages of letting him have a chance to outdraw me, or he could be value bet‐ ting with 7‐7 – J‐J. A couple of reasons to call here are if the oppo‐ nent is tough and will call down light or if the opponent will bluff again if I call, but none of those applied here so I raised the pot and he quickly folded.