- Trump color can be played despite color preference as your turn’s play.
- Trump color is the color of the starting card or the top card of the trump deck, unless the color is wild, then the first person chooses.
- A wild plus four can either change trump color or the color in play (hand color).
ii. Draw stacking
- Twos, fours, plus twos, and plus fours, can add to and pass on the draw card count.
- Reverse and skip can also affect the draw card count. Reverses pass the draw stack back to the previous player, and skips pass on the draw stack to the next player.
- If a player draws equal to or more than 10 cards they may give away three cards as they please.
- A card can be discarded to no effect if it is the same color and either the same number or one below or one above as the played card.
- Plus twos and plus fours may be discarded as twos and fours respectively.
- If a run of three or more is played, then the one who finished the run can play an extra card as if it were their turn; this does not affect play order.
- If someone adds to the run (that is, turns a run of three into a run of four, etc.) they have overran the original run and steal the extra play from the other player.
- If special card has been played, you may play another special card on top of it to either add to or negate it’s effect.
- If you have four of one number, all different colors, than you may play them all at one time.
iv. Special Wilds
- Special Wilds (any card not included in the very first original Uno; for example, the attack card in Uno Attack) can be any card that exists in the deck.
- Special Wilds can also be played as a mandatory plus eight; it cannot be blocked, passed on, or canceled. If a mandatory plus eight is played during a plus stack, it cancels out whatever the stack had added up to before and simply becomes a mandatory plus eight to the next player.
- If a plus infinity is played the victim can clap twice to negate it’s effect and any additional draws.
v. Special Cards
- Zeros. Zeros cause players to trade hands to the left; this can be affected by reverse and skip.
- Sevens. If a player plays a seven they may give away two cards distributed as they like. They can not win this way (e.g. by playing a seven and giving their last two cards away to win.)
vi. Cool Numbers
- The cool numbers are 69, 420, 777, 42, 95, and 66.
- Cool numbers can be discarded together. For example, a red 9 could be discarded on top of a red 6, as together they would make 69.
- They must be discarded in order. You cannot discard a red 6 on top of a red 9, as that would be 96, which is not a cool number.
vii. Interesting Numbers
- The interesting numbers are 666 and 24.
- These numbers have no affect on gameplay, they are simply canonized as being interesting numbers.
viii. Color Confusion Rule
- At the end of many cards being played then the current color is the color of the most recent non-wild card.
ix. Optional Rules
- William’s Rule. When William’s rule is invoked, twos and nines are interchangeable. A two can be played as a nine and a nine can be played as a two. This applies to stacking, runs, etc.
- Karsten’s Rule. When Karsten’s rule is invoked, you play with however many cards the dealer has dealt, even if it is above or below the normal seven cards.