Secrets of the Amateurs

An interesting hand played out in a single table yesterday, and it goes to demonstrate how there are a few more characters around now who know the score.

I'm on the big blind with 900 after posting, blinds are 50-100. The button has been aggressive but seems to know what he's doing. I've made one all-in that was uncalled, and that's all I've done. I figure that if it's passed round to the button and he makes a raise that I can knock him off, I'll just reraise him with any two. And so it comes to pass, he raises to 300. I have a look just for show and push. He's now getting 2/1 on this call. He calls very quickly, I say "oops" and show J6 off. He shows 87 and I win.

Even the dealer said "wow", and most of the other players had their jaws on the table. I ran into the guy later and we had a laugh about it, we both knew what the other player was doing. For a while I was wondering, if he was so sure I was going to steal reraise, why make the play with 87 in the first place. But basically he wasn't. He raised, knowing that I might be aware of the steal reraise play. When I did reraise, there were two possibilities. 1) I have the steal reraise play in my locker and 2) I don't. If it's 1) then clearly I can have any two cards. If it's 2) then I have a real hand, at most 10% of my possible holdings. If it's 50/50 that I know the steal reraise play, then by Bayes theorem I will be on the steal 5 out of 6 times !

Working this out offline, 5 times out of 6 I have any two and he is 44% to win the hand with 87 [1]. 1 time out of 6 I have let's say A7/KQ/44 or better and he's 33%. Even if my range is as narrow as AT/77 (and surely even a total rock would reraise with at least these) he's 30%. The weighted average of his chance is 42%, massive compared to the 2/1 pot odds. Basically if there's any chance I'm steal reraising here he has to call, because he has a borderline call even against the "real" range of A7/KQ/44.

All in all it's a clever play. He hasn't gone all in because the small blind has him covered and if 300 won't chase the small blind off then it's not very likely that any more will. And even if, unbeknownst to him, I will always reraise then he's 44% to win 2100 which is a return of 850, only a 50 chip loss. I shall have to look for opportunities to make this play myself in future, I'm sure I have missed a few so far. Sure if it's just me and him he's better off setting me all in, but the presence of the small blind makes the normal raise/call the best option.

[1] Yes, 87 offsuit is 44% against any two cards. More than you thought, isn't it ?