with a four flush on the board and a hand like three of a kind you bet the flop, 2/3 of the pot is usually a good amount.
3 things can happen based on how aggressive your opponent is:
- They fold (this will never happen especially against donkeys that have top pair, or draws.
- They raise (This could mean again, anything, top pair, three of a kind as well, or even a draw.) which you should call with 3 of a kind and top kicker.
- They call (this would definitely make me suspect a draw, but top pair as well.)
If 3 of the same suite come on the board on the turn you can value bet again,
They fold
They raise (this means they almost definitely made a flush or something even better like a boat.)
They call (suspicious, there is absolutely no reason to call here unless your slowplaying or hoping to suck out.)
If no made flush, they are one in five to make the flush, raise huge here overbetting the pot, if they call or go all in on the draw you are way ahead. If they hit it on the river, you lose, but going all in before the river makes sense for two reasons.
With a four flush and one card to come, many experienced players fold here knowing its not worth the gamble and they're probably drawing dead to their flush.
Tight inexperienced players will call hoping to hit the flush. Loose inexperienced players may also call, or even push all in.
1/5 to hit the card is not a lot, if you're all in and 80/20 going to the river you've played the hand extremely well, if they hit its just variance, most of the time this is going to be a winner for you.
Now, say you don't bet or shove it all in on the turn, say you check, the flush draw will check back or maybe semibluff a small amount. You will both see the river.
No flush card
You bet out, they fold. You recieve the minimum possible.
Flush card (that doesnt give you a boat.)
you bet out, they shove all in, you lose no matter if you call or fold.
Neither of these options are very appealing, but they are the two only options that are going to happen if you see a cheap river (unless you're up against a player who will try to bluff at it with a busted flush).
Betting/shoving the turn allows for max value to be made out of the hand, its the same thing as getting it all with AA against KK preflop, you wont always win but the majority of the time you will, which is why its the best possible move.
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How to detect the flush/straight
A lot of good players recommend playing suited connectors from position, its all that Daniel Negreanu seems to play, observing players at the table is key here, are you seeing people who are showing down with suited cards or connected cards? (even donks usually only play higher unsuited connectors, so you dont have to worry much about losing to 34o) these are the people that are gonna be chasing that flush, if they're betting out on the river when you've appeared strong the whole way and they just called you down, they've probably made their draw. Watch for these guys, they can be real trouble, but they can also be really predictable if you know what to look for.