this site would be ideal for duplicate poker. i.e. have an hour tournament with 10 hands against each opponent with results compared. Also a great way to learn: see what others did on the same deal.
Duplicate poker was tried some years ago, but full table…just didnt work
Duplicate poker does have some benefit of reducing variance in the game, but I’m not so sure how to make it work well.
Unless I’m mistaken, I think the full table duplicate poker that once appeared online was an attempt to get around certain US gaming laws by claiming that it was a game of skill (and therefore legal) while regular poker was a game of luck (and therefore illegal). And because the motivation for creating duplicate poker was legislation rather than making it fun to play, it was actually pretty easy to predict it would never become popular. (And while this is irrelevant to our discussion, their whole claim that a format with slightly lower variance would be a "game of skill" while a version with slightly higher variance is a "game of luck" was absurd to me as well. But then again I’m a mathematician and not a lawyer so I wouldn’t really know if the claim could hold up in court or not…)
In heads-up games the duplicate format might work a lot better and actually be a lot fun to play that way, but to get the maximum variance-reducing benefit each player would need to play each hand multiple times, twice against each opponent (and play "both sides" of the same hands). And unfortunately that would not work because the players would then know what their opponents hold in certain hands where the board repeats and the player already played the other side of the hand.
A team of two players playing against another team of two players could be used to solve this particular issue (as it has in certain man vs. machine match-ups), but only if you can trust that the players are honest and don’t share their hands with their team mates.
I do agree though that this could be a great format for Correspondence Poker if there was a way to guarantee the honesty of the game, but cheating would also be so easy that I’m not sure if I’d enjoy playing this format against people that I didn’t already know and trust. In private tournaments, or some other similar setups, this might be a fun way to play though.
It might also be possible to come up with some other "semi-duplicate" formats, for example where the whole cards were duplicated but boards were not (to prevent knowing what your opponent holds on a board you’ve already seen), but that would have it’s own complications too and not be as trivial as it may sound at first. And in case the variance was reduced only slightly but not significantly, it might not even be worth it anyways if it just made the game more complicated with little added benefit.
If you do have any other ideas, either regarding the duplicate poker format or something else, please feel free to share them here. I will keep the duplicate poker idea in mind in case we can figure out a cool way to implement it. And in any case, thank you so much for sharing the idea, Bill.