Oh Shit is a classic trick winning card game. Played with a full deck of standard playing cards without any Jokers. It is a close cousin to the game Oh Hell and has varying rules depending on where it is played. These are the rules that playohshit.com uses.
The aim of the game is to score more points than your opponent.
There is a total of 19 rounds in the game. The number of cards dealt to each player is determined by the round. Ten cards are initially dealt and then one less each consecutive round until only one card is being dealt. After the one card round an additionally card is dealt each round until there are 10 cards dealt.
The following steps are repeated for each round:
Card values from lowest to highest are: 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, A. Hence an ace would beat any other card and a 2 would beat nothing. The exception to these values is if a card is a trump. The highest trump card is the Jack of the trump suit and the Jack of the same colour also becomes a trump and is the second highest card in the game. Hence, if spades was trumps the highest valued card in the game would be the Jack of Spades and the second highest would be the Jack of Clubs. Under these circumstance the Jack of Clubs would be played at any time a spade could be played.
After the cards are dealt each round, a card is turned over and its suit is declared the trump for the round. A trump like any other suit can only be played if it is lead or if a player does not have any cards of the suit that was lead. However, unlike other suits, if a player can't follow suit and instead plays a trump the highest trump will beat all other cards regardless of their values. Hence, if spades was trumps, a player lead with the Ace of Hearts, the next player didn't have any hearts and instead chose to play a Two of Spades because it is a trump card the second player would win the trick.
As noted earlier the Jack of a trump suit is the highest card in the game. Furthermore, the Jack of the same colour in the off-suit is the second highest. The off-suit trump for the all purposes in the round becomes the trump suit.
At the beginning of each round, after looking at their cards, players bid how many tricks they expect to win. Bidding starts with the player to the left of the dealer. As a result, the dealer always bids last. The dealer may not make a bid that will result in the sum of player bids for the round being equal to the number of cards in the round.
At the end of each round, players are awarded one point for each trick they won. Furthermore, players who achieve their bid exactly are awarded a bonus 10 points for the round. Notably, players who win more than what they bid do not receive the bonus points.
Read about Oh Hell! rules and other great card games.