Who shows first on check-check river

[Pokerron]

I thought it was the person who checked first?

I've been told:

River was check-check.   You bet the turn, which your opponent subsequently called. The showdown begins with the last player to bet or raise, regardless of in which round of betting this occurs.

[Bongo]

I've been told:

River was check-check.   You bet the turn, which your opponent subsequently called. The showdown begins with the last player to bet or raise, regardless of in which round of betting this occurs.

That is my understanding of it.

[matt674]

i always understood if it went check-check on the river then the first person to speak (ie the person first to act after the button was the first to show their hand) regardless of any action that took place on the turn.

Then again it may be different casinos having different rules. Usually you find that whoever thinks they have the best hand is normally the quickest to flip their cards!! 

[Pokerron]

The response I posted was from a online site after I questioned why it happened in a heads up game.  It was news to me!

[Royal Flush]

I always thought the last person to bet showed aswell