Reraise to isolate?

[jaguar]

I watched this prima poker stream yesterday and one of the commentators was constantly talking of how the players didnt reraise enough to isolate from the button. I didnt understand anything of what he ment so can anyone please explain this play. I take a example hand from yesterdays broadcast.

6max game 25/50 all have at least 100BB stacks

All fold to cutoff who opens for 4BB with QTs
Button with KJs called

Commentator now starts telling that in this situation you have to decide if your hand is better or not and either fold or reraise to isolate. I simply dont understand what a reraise would gain you. Can someone elaborate.

[MoDOH]

An openraie from CO doesn´t say much about the raisers hand as he could pretty much raise any cards here trying to steal the blinds.
A reraise though usually means a pretty big hand and therefore earns more respect, as it should.
So with a strong hand as KJs OTB against a CO openraise a reraise should be in order against aggressive (LAG:s?) players like these. You will more often than not get it HU and often you will win the pot right there.
When it´s HU you are IP and you have the initiative, a powerful combination in NL-Hold´em. And will more often than not win the pot with a bet on the flop.

So the upside of rerasing is that.
1. you might win the hand right there.
2. You get the pot HU and gain the initiative so you can win the pot postflop UI.
3. You might fold out a better hand, KQ and AJ for example...

The upsides of just calling is that the blinds are still relatively small and with a hand like KJs he is perhaps hoping to flop something nice so he can take down a big pot. By calling you induce the blinds to tag along too creating a multway flop.
since these guys are so confident in their postflop abilities he might figure that with the best position and a decent hand he might as well see a flop and take it from there...

[XXXNoahXXX]

Reraising to isolate basically means that you are reraising to knock out other players that might call the original raise. Say 4 players would call the CO's raise, but when the KJ reraises, it might make 0 of them call, so KJ gets to go heads up. When you think you're hand is strong u dont want hands like 10 J suitewd and whatnot calling on speculative draws. A perfect example is that AA is the best hand preflop, but if all ten players see a flop, there's a high likelihood someone will outdraw. If AA raises to isolate one or two players, the odds of him getting outdrawn are much less.

[jaguar]

Thanks for t good explanations, the thing is still dont understand with the play is that if you get called wouldnt you in 95% of the cases be behind. since i have a hard time imagine any halfway decent player calling a reraise with a worse hand than KJs in a normal game.

[XXXNoahXXX]

As explained, a raise out of the CO is often an attempted blind steal. However, depending on the size of your reraise they might call just to see the flop since they already have some chips invested. If you reraised with JK and someone in early position was the original raise and called, it'd be a whole different story. Basically, a fold preflop to your reraise is optimal, and if not, proceed with caution.