UNO Rules

This is the standard matching game, not a house stack and not a bluff-heavy variant. Duetly's server checks every play. A modified client cannot invent a card, skip someone else's turn, or play Wild Draw Four while holding the current color.

The deck

• Four colors: red, yellow, green, blue.
• Each color: one 0, two of each 1–9, two Skip, two Reverse, two Draw Two.
• Four Wild and four Wild Draw Four.
• 108 cards in total.

Opening card

If the first discard is Wild Draw Four, it is buried and replaced. If it is Wild, the first player names the color and then plays. Skip skips the first player. Reverse flips direction; with two players it skips the first player. Draw Two gives the first player two cards and skips them.

Legal plays

A card is legal if it shares the current color, shares the number or action symbol of the top card, or is a Wild. After you draw, you may play only that drawn card — not a different card from your hand — and only if it is legal.

Wild Draw Four restriction

You may play Wild Draw Four only when you have no card of the current color. Matching a number in a different color does not block it. Holding a red 5 while the color is red does. There is no challenge round on Duetly: an illegal Wild Draw Four is rejected before it hits the table.

UNO

Declare when you have two cards (before the play that leaves you with one) or immediately after you are down to one. If you do not, you are vulnerable until the next player acts. A callout draws two. You cannot call out yourself.

Empty draw pile

When the draw pile runs out, the discard pile is shuffled back except for the top card. If nothing remains to draw, the turn passes.

What is not a rule here

• No stacking Draw Two on Draw Two.
• No playing out of turn.
• No showing other players' hands.
• No jumping in with a matching card off-turn.