With exactly two players, the blinds swap around — and half of experienced home games get it wrong. Here is the official ruling, why it exists, and everything else that changes head-to-head.
Heads-up (TDA Rule 34-B, and Robert’s Rules agrees word for word):
So the same player is simultaneously the dealer, the small blind, first to speak preflop, and last to speak on every later street. Once you’ve played it a few times it feels natural; the first time, everyone thinks the dealer is cheating.
The common home-game mistake
Dealing the button the big blind “because the small blind is always left of the button”. At three or more players, yes. At two, the rule above overrides — otherwise the same player would act first on every street, which is exactly what the official rule exists to prevent.
Try the naive version: button = big blind. Then the small blind acts first preflop and first postflop — one player gets the worst of it on all four streets, every hand. The official arrangement splits the disadvantage: the button pays the smaller blind and speaks first once (preflop), then enjoys last action for the rest of the hand. Combined with the button alternating every hand, both players get exactly the same deal in the long run.
Sanity check
“First card left of the button” still holds — heads-up, the only player left of the button is the big blind. The heads-up rules aren’t exceptions to the normal dealing logic; they’re the normal logic applied to two seats.
Someone busts from a three-handed game — who has the button in the first heads-up hand? The guiding principle in both major rulebooks: no player should post the big blind twice in a row.
Practically: look at who paid the big blind last hand; the button goes to whichever arrangement doesn’t make that player pay it again. The player who most recently had the big blind takes the button.
Director’s call
Rooms differ between “dead button” and “moving button” conventions in messy multi-elimination cases, and a tournament director’s ruling is final. The no-double-big-blind principle is the constant every convention tries to protect.
No-limit and pot-limit betting are completely unchanged: same min-raise rule, same all-in rules. The one difference worth knowing is in fixed-limit: the usual cap of one bet plus three (or four) raises per round is typically removed heads-up — two players may keep re-raising each other until one is all-in.
Cards speak, best five of seven, identical hands split — the rankings page applies unchanged.
Two sentences of strategy
Heads-up, hand values rise dramatically — any pair or ace is a strong holding, because there’s only one opponent to beat, and the blinds hit you every single hand, so waiting for premium cards is itself a losing plan. That’s all the strategy a rules page needs.