I am running a sim in pio where HJ 3B UTG+1.

Flop was Th, 5d, 3c

HJ bet 1/3 pot, UTG1 calls

Turn is Jd

HJ bets 1/2 pot and Pio is saying you call with 99 and 88 only when you have a diamond. why is that? Doesn't the diamond block HJ's continued bluffing range where he cbet and then got a FD on the turn?

I would think that its worse to have a diamond in your hand?

I also notice that PIO is saying to call all A5 and A3, but fold most 99 and 88. Why?

Diamond makes it so that when you hit a set otr, flush never hits at the same time.

What has higher equity vs KK? 99 or A5?
A5 also has way better blockers.

As well as being able to hit a set that doesn't complete the flush, you also reduce the chance that villain actually binks the flush when he's semi-bluffing, as your 9d means he only has 8 outs.

A5/A3 have more outs when behind (up to 5 each to make trips/two pairs) than 99 (just 2 to a set).

so are you only considering the blocking effects of holding the diamond on the river and not the turn?

I was thinking that holding the diamond was bad because it lowers the probability V has a flush draw, which would seem to increase the possibility he has a J or a 10 which beats you?

It also increases the probability that he has a bluff that isn't a flush draw. Which is good for us.

We'd rather see that he's bluffing without a flush draw than with.

This is a topic that I wanted to open for some time now, so I gladly put myself in the speech.

What are the situations in which it is better not to have a card that can block its flush draw? We often hear people say when they are reviewing hands or watching players who are streaming say "it would have been better to call without having a heart in your hand etc .." Why?

Can it change the dynamic if we are attacking or bluffing catching?

Yes, that makes sense. All I'll say for now is that blockers and anti-blockers are incredibly confusing and I mistakes with them all the time, because it's often very hard to know in the moment whether you block more value hands, or more bluffs, and it's hard to judge how much equity your hand has vs an entire range. In some spots it's very clear that you want to block some "obvious" value hands, more than you block some "obvious" bluffs, and in other spots the exact opposite is true. More commonly you have a combo that blocks some value and some bluffs, and it's not at all clear to which degree the effect is strongest. :/
It's a bit like how hands have differing equity depending on exactly what the opponent has. If the board is A72 with two diamonds, and villain has 77 (middle set), you'd much rather have two random diamonds than AK (as top pair is drawing almost dead), but if he has AQ, you're loving life with AK. Likewise 99 beats a flush draw on A72, and even has equity vs middle set, but it's pretty weak vs most value hands, as it only has 2 outs. How each hand does against a range as a whole requires careful exploration with a solver, in order that you can establish which "blockers" are most significant.

Yes this is a very tricky topic to fully understand

1. Paired boards will sometimes give different results..because now if you hit the 9d ..he xan make a flush while you boat up.

2. Rank of the flush blocker in your hand seems to matter

3. Your other card seems to matter..does that other card block flopped bdfd?

4. Board texture will matter..are high cards of the flush draw already on board..is a high card on board non flush card ? (Making more combos of pair + fd possible)

I dont think there is any easy solution here. Just explore as much as you can and detect patterns.