Uno uses its own deck of one hundred and eight cards in four colours — red, yellow, green and blue. Each colour holds the numbers zero to nine, with a single zero and two of everything else, plus three cards that interfere with the next player. Separately there are the wild cards, which belong to no colour at all. Anywhere from two to ten people can play. Everyone is dealt seven cards, the rest becomes the draw pile, and one card turned face up starts the discard pile.
How a hand is played
Play passes around the table one player at a time. On your turn you must cover the top of the discard pile with a card that shares its colour, its number or its symbol: on a red seven, any red card and any seven will do. If nothing in your hand fits, you take a card from the draw pile and play it straight away if it is playable; otherwise the turn moves on. The hand ends the moment one player has no cards left. If the draw pile empties first, the discards are shuffled back into a new pile with the top card left face up.
Action and wild cards
Three of the coloured cards do more than match. Skip costs the next player their turn. Reverse flips the direction of play, which with only two players amounts to a skip and hands the turn straight back. Draw Two forces the next player to pick up two cards and miss their go. The two wilds work on any colour: the plain wild can be played at any time and lets you name the colour that continues, while the wild draw four does the same and makes the next player take four cards. That last one is meant to be played only when you hold nothing in the current colour, and a suspicious opponent may ask to see the hand of the player who used it.
Calling uno
When you play your second-to-last card and only one is left, you have to say so out loud. Forgetting is punished if an opponent catches it before play has moved past you: the standard penalty is two cards, though several later editions ask for four. It is worth agreeing which version you are using before the first deal, because this is the rule tables argue about most. Once the call has been made it stands — being skipped or blocked afterwards does not oblige you to call again.
Counting the cards left in hand
The player who runs out of cards wins the hand and scores the value of everything still held by everyone else. Number cards count their face value, from zero to nine. Skip, reverse and draw two are worth twenty points each. Both wilds, the colour change and the draw four, are worth fifty each. The losers show their hands, the totals are added up, and the whole amount goes to the winner while everyone else stays where they were. Saving a wild for the perfect moment is therefore a gamble: if somebody goes out first, that one card alone hands them fifty points.
Playing to five hundred
Hands continue until a player reaches five hundred points, and that player wins the game. With only two or three at the table each hand is worth less, so many groups drop the target to two or three hundred to keep the session short. There is also a reverse scoring variant in which each player counts the cards left in their own hand and is knocked out on passing a limit, but that is a different game and has to be agreed before the first deal.
Keeping score with Score Buddy
The Score Buddy scorer for Uno is set to a target of five hundred points. Its quick buttons are +10, +20 and +50, chosen to mirror the card values: tap +20 once for each skip, reverse or draw two left in opponents' hands, +50 for each wild, and use the keypad for the numbers. At the end of a hand tap the player who went out, enter the total they collected and confirm. The standings reorder themselves and each card shows how far that player still is from five hundred.