It is the game played only once per year across Australia.
But when it's on, boy, do people get into it.
Synonymous with Anzac Day, two-up is illegal on most other days except for today, mainly because it's an unregulated form of gambling.
While it is pretty unclear when the game really started, we know that during the First World War, diggers would play two-up to beat boredom.
At present, the game really gets going once the Anzac Day march and 10am service are complete.
A firm fixture at the Katherine Club, two-up draws punters ready for a bet, and today was no exception.
RSL Member Andy Harris has seen his fair share of games as the main man taking bets for the past 15 years or so - he can't quite recall how long he's had the gig, but it has been a while.
He says the rules are simple, but the stakes are high, and that is why people love to play.
"Even though a lot of people don't know the rules first off, they like to get involved. It takes a couple of minutes, or less to explain how to do it, and it is easy to follow."
He said the traditional game is all the more popular because of the strict rules about when it can and can't be played.
"You can only play once per year, and that makes it kind of special. People make a point of coming down to get involved," he said.
Katherine was buzzing before sunrise with many people attending a service to remember those who have fought in conflicts around the world.
Hundreds of resident's marked the 104th anniversary of Anzac Day with a Dawn Service, laying wreaths and pausing to commemorate past and present service men and women.
The spirit of Anzac continued with a march to the Cenotaph, where a memorial for fallen soldier Scott Palmer was held.
Anzac Day marks the landing of Australian and New Zealand forces at Gallipoli.