How two-up works and where you can play

Australian Imperial Force soldiers playing two-up in a camp compound, 1941. Photo: Truth (Brisbane, Qld.), Public domain

The people and the gear

RSL Queensland, which publishes a plain-language guide for its sub-branches, uses the same vocabulary you will hear in any ring. The spinner is the punter throwing the pennies. The boxer (also called the ringkeeper) takes and pays the spinner's bet and makes sure the game is run fairly; the boxer's decision is final. The kip is the flat paddle the pennies sit on before the throw. The ring is the marked space where the coins must land, and the school is the crowd betting around it.

There are only three results. Heads means both pennies show the monarch's head. Tails means both show the reverse. Odds means one of each, and odds settle nothing.

A spin from start to finish

The sequence below follows the order described by RSL Queensland. House rules on details such as stake sizes vary from venue to venue, so the boxer's call on the night always wins.

1. The boxer picks a spinner. The spinner places a bet, and the boxer finds another player to cover it with an opposing bet of the same amount.
2. The school bets among itself. Side bets are struck player to player around the ring, one punter backing heads and another backing tails for the same amount. RSL Queensland notes typical side bets of $5 to $20.
3. The coins go on the kip tails-up. Two pennies are laid on the kip with the tails side showing.
4. The throw. The spinner tosses both pennies at least 3 metres into the air.
5. The ruling. Two heads or two tails landing inside the ring settle all bets. Odds, a coin on its edge, or a coin outside the ring means a rethrow, with every bet left standing.
6. Settling. The spinner can only win by throwing heads. Tails ends the spinner's bet and the kip passes on. Side bets are paid directly between the two players who struck them.

The maths of a single throw

Each penny lands heads or tails with probability 1/2, and the two coins are independent. That gives four equally likely outcomes: HH, HT, TH and TT.

• Heads (HH): 1 outcome in 4, so 1/4 or 25%.
• Tails (TT): 1 in 4, so 25%.
• Odds (HT or TH): 2 in 4, so 50%.

Because odds is simply thrown again, what matters for betting is the chance of heads given that the throw counts: 0.25 ÷ (0.25 + 0.25) = 0.5. Heads and tails are a true 50/50.

How long a decision takes

Half of all throws are odds, so a throw settles the bet with probability 0.5. The expected number of throws per decision is 1 ÷ 0.5 = 2. A run of odds is common: three in a row has probability 0.5 × 0.5 × 0.5 = 1/8 (12.5%), and five in a row 1/32, about 3.1%. Long odds runs are normal chance, not a sign of a rigged kip.

Why a traditional ring has no house edge

A side bet of $10 on heads against $10 on tails pays even money on a 50/50 event. The expected value is 0.5 × (+$10) + 0.5 × (−$10) = $0. Nobody is building in a margin, which is the opposite of a casino table, where the payout is set slightly below the true odds. Our page on which casino games return the most shows how that margin looks on roulette and blackjack.

The no-edge rule holds only where no commission is taken, and the states treat that differently. Western Australia's two-up policy says that, unless a permit condition prohibits or restricts it, the ring keeper may take a customary commission of up to 10% of the spinner's winnings (after the spinner withdraws) and of the winnings of players who bet through the ring keeper and win on heads. Work that through for a $10 heads bet placed via the ring keeper: a win pays $10 less 10%, so $9, and a loss costs $10. The expected value is 0.5 × $9 − 0.5 × $10 = −$0.50, a 5% edge against the punter. In Queensland, by contrast, the government's guidance says all money wagered must be returned to players as winnings and no commission can be charged.

The spinner's run

A spinner who stays in for several heads needs each to come before a tails. Since every counted throw is 50/50, two heads in a row is 1/4 and three heads in a row 1/8. Odds throws in between change nothing; they only add time.

Where and when it is legal

Outside the exemptions below, the game is unlawful gambling. Each exemption has its own days, venues and money rules, which is why the same game is run differently in Perth, Hobart and Sydney. Our overview of gambling law across the states covers the wider framework.

State and territory exemptions, from the legislation or regulator guidance listed in the sources.

For the ACT and the Northern Territory we could not open a current regulator page, so the table relies on RSL Queensland's state summary; check with the ACT Gambling and Racing Commission or the NT regulator before running a game there.

Details that trip people up

• Western Australia counts hours. A standard permit outside the Perth radius allows a maximum of six hours of play, and only two coins or two dice may be used. No admission charge may be made and under-18s may not play or help run the game.
• Victoria counts days. The seven-day lead-in belongs to RSL sub-branches only; a pub gets Anzac Day itself and nothing else.
• Tasmania counts the clock. A game still running at 6.01pm on 25 April is outside the exemption.
• New South Wales counts the calendar. 11 November is covered only after 12 noon.

Keeping the day in proportion

The game is short, loud and social, and most of the money changes hands in $5 and $20 notes. The maths still applies: a 50/50 bet repeated all afternoon has no way to come out ahead on average, and a commission ring is slightly worse. Set a cash amount before you walk in and leave the cards at home. If a day at the ring turns into chasing losses, Gambling Help Online runs a free, confidential line on 1800 858 858, open around the clock, and our safer gambling page lists the other tools available in Australia.

Online, the coin is replaced by software. If you ever see a digital version, the fairness question becomes one about the random number generator, which we explain in our guide to how casino RNGs are tested.