Euchre is a trick-taking card game played in many parts of the world. It is closely related to the French game Écarté.

Geography/History
The United States, the British Isles (most notably in Cornwall), Canada and Australia all have large followings of the game. In the United States, euchre has declined in popularity since the 19th century, when it was widely regarded as the national card game, but it retains a strong following in some regions. Today, although euchre players can be found across the United States, the game is most predominant in the upper midwest as well as Pennsylvania and upstate New York — all areas with significant populations of German-Americans who settled in those areas during the 19th century. In Canada, euchre's largest following is in Ontario.


Dealing
Conventional euchre is a four-player trump game, wherein the players are paired to form two partnerships. Partners face each other from across the table so that the play of the cards in conventional clockwise order alternates between the two partnerships.

Conventional euchre uses a deck of 24 standard playing cards consisting of A, K, Q, J, 10, and 9 of each of the four suits. A poker deck can be used, omitting the cards from 2 to 8, but a pinochle deck may be divided in half to form two euchre decks.

Each player is dealt five cards in clockwise order, usually in groups of two or three cards each. The remaining four cards are referred to as the kitty or the blind and are placed face down in front of the dealer toward the center on the table. The top card of the blind is then turned face up.

When a suit is named trump, any card of that suit outranks any card of a non-trump suit. The highest ranking card in euchre is the jack of the trump suit and is referred to as the right bower. The second highest ranking card is the jack of the suit of the same color as the trump suit; this card is called the left bower. Remaining cards of the trump suit rank from high to low as A, K, Q, 10, and 9.

In non-trump suits, the jacks are not special, and the cards of those suits rank from high to low as A, K, Q, J, 10, and 9.


Example
Assume a hand is dealt and that hearts are named as trump. In this event, the trump cards are as follows, from highest ranking to lowest:

jack of hearts (right bower) 
jack of diamonds (left bower) 
ace of hearts 
king of hearts 
queen of hearts 
10 of hearts 
9 of hearts 
For the purpose of play, the jack of diamonds becomes a heart during the playing of this hand. This expands the trump suit to the seven cards named above and reduces the suit of the same color (sometimes referred to as the next suit) by one card (the jack "loaned" to the trump suit). The same principles are observed for whatever suit is named trump. Remembering this temporary transfer of the next suit's jack is one of the principal difficulties newcomers have with the game of euchre.

Once the above hand is finished, the jack of diamonds ceases to be a heart unless hearts are again named as trump during the playing of the subsequent hand.


Play

Objective and scoring
In euchre, naming trump is sometimes referred to as "bidding". When naming a suit, a player asserts that his or her partnership intends to win at least three of the five tricks in the hand. A single point is scored when the bid succeeds, and two points are scored if the bidder takes all five tricks. A failure of the bidding partnership to win three tricks is referred to as being euchred (also called getting set) and is penalized by giving the opposing partnership two points. A bidder with exceptionally good cards can go alone, in which case he or she seeks to win all five tricks without a partner. The partner does not play and if all five tricks are won by the bidder, the winning partnership scores four points.

The primary rule to remember when playing euchre is that one is never required to trump, but one must follow suit if possible to do so.


Bidding (naming trump)
Once the cards are dealt and the top card in the kitty is exposed, the upturned card's suit is offered as trump to the players in clockwise order, beginning with the player to the left of the dealer. If the player wishes the card's suit to become trump, he or she bids by asking the dealer to "pick it up" (referred to as ordering up a card). In this event, the dealer takes the card, adds it to his or her hand, and then discards one card, placing it face down on the kitty without displaying it to the other players. Once a bid has been made, play begins.

If a player does not want the upturned card's suit to become trump, he or she says "pass" or signifies the desire to pass by knocking on the table. The next player to the left may then order up the card or may likewise pass.

If the upturned card comes around the table to the dealer without being ordered up by any of the players, the dealer may make a bid by picking up the card, adding it to his or her own hand, and discarding the extra card as described above. The dealer may also decline the upturned card's suit by turning it face down on the kitty. Once this suit has been passed by all four players, it may no longer be chosen as trump.

If the upturned card's suit is not chosen by any of the four players, the players are offered the opportunity to name any of the other three suits as trump, beginning with the player to the dealer's left. In this case, play begins as soon as a suit is named; no cards enter or leave the dealer's hand. A player may pass as previously described, and if the bidding comes around the table to the dealer without the naming of a suit, the dealer may name a suit. If he or she also declines to name a suit, the cards are collected, no points are scored, and the deal is passed to the left.

In some variations, the following rules are added during the bid. First, if the dealer's partner orders up the dealer, the dealer does not play in the hand and the dealer's partner must play alone against two defenders (described further below). Second, if all players pass the bid twice, the dealer is stuck making trump from the remaining three suits (i.e., cannot opt for a redeal. Also, this rule is sometimes known as "stick-the-dealer"). These additions are sometimes referred to as "Canadian rules."

The team that selects trump is sometimes known as the "makers" for the remainder of the hand. The opposing team is known as the "defenders" for the remainder of the hand.


Winning tricks
The player to the dealer's left begins play by leading a card. (If the player to the left is sitting out the hand because his or her partner is going alone, the dealer's partner will lead.)

Play continues in clockwise order; each player must follow suit if they have a card of the suit led. Remember that the left bower is a member of the trump suit and is not a member of its native suit.

The player who played the highest trump wins the trick. If no trump were played, the highest card of the suit led wins the trick. The player that won the trick collects the played cards from the table and then leads the next trick.

After all five tricks have been played, the hand is scored. The player to the left of the previous dealer then deals the next hand, and the deal moves clockwise around the table until one partnership scores 10 points and wins the game.


Going alone
If the player bidding (making trump) has an exceptionally good hand, or if his or her partnership is in danger of losing the game unless they are able to quickly score points, the player making trump has the option of playing without his or her partner. If the bidder playing alone wins all five tricks in the hand, the team scores four points.

"Going alone" is initiated at the time the bidder orders the upturned card on the kitty to the dealer (on the first round of bidding) or names a suit (during the second round of bidding). The bidder signifies his/her desire to play alone by stating "alone" or "spades alone" after bidding but before play begins.

During a loner, the bidder's partner discards his or her cards, and does not participate in play of the hand.

Naturally, the odds of success of a loner bid depends on the lay of the cards, and in loner play, the inactive cards held by the bidder's partner means that nine cards out of 24 do not participate in play, making play less predictable than otherwise. A hand consisting of the top five cards of the trump suit, are mathematically unbeatable, while other combinations merely have high probability of outranking one's opponents' cards.

A loner bid that fails to win all five tricks is not penalized; the bidding partnership scores one point provided that they won three or four tricks.

Scoring

The first team to score 10 points wins the game (sometimes called a round). While score can be kept by using a tally sheet, most euchre players traditionally use the unused 6 and 4 cards for one member of each partnership to keep score; in this case, one card is used to cover the other so as to expose the number of pips corresponding to the team's score.


Cheating
As mentioned above, Euchre is a game of etiquette. For this reason, there are several opportunities to cheat. Some of these breaches are significant enough to have become a permanent part of the game, either as an accepted part of the rules, or as part of specific variations. Some of these include:

Failing to offer the cut: When a dealer fails to offer the opportunity to cut to the player to his right, after shuffling and before dealing. When caught, the dealer forfeits his turn to deal and passes it to the next player. 
Reneging: Failure to follow suit when able. When it is noticed, the hand is generally forfeited, and 2 points are awarded to the opposing team. Because of the fast pace of the game, catching a reneger is difficult. 
Stealing the deal: When a player either intentionally or accidentally deals out of turn. Depending on the variation(s) played, there is a slight advantage to being the dealer, as the making of trump based on the upcard automatically gives the dealer one trump card. When it is noticed, the hand is generally forfeited, and 2 points are awarded to the opposing team. 
Table talk/signals: When a player or team intentionally communicates the contents of their hands to each other or otherwise interferes with otherwise objective play. When caught, the hand is generally forfeited and 4 points are awarded to the opposing team. 
Stacking the deck: When the dealer arranges the cards prior to the deal so that he and his partner become more likely to win. 

Variations in play
Variations in game play are generally invoked by agreeing on them before play begins.


Throw-ins
These variations (and others) allow a player dealt one of several types of poor hands to "throw in" their cards and initiate a redeal. In some circles, these are considered a form of "misdeal", causing the deal to be passed to the original dealer's left.

Nines & Tens: a hand consisting only of 9's and 10's. It is impossible for more than one player to have such a hand in regular play. 
Ace, No Face: a single ace and nothing else except 9's and 10's containing only non-trump. 
King Nothing: a single king and nothing else except 9's and 10's containing only non-trump. 
Bitches' Hand: three queens and nothing else except 9's and 10's containing only non-trump. 
Jack Shit: a single jack and nothing else except 9's and 10's containing only non-trump. 
No Ace, No-Face: a throw-in hand determined after the make, containing only non-trump 9's and 10's. 

Farmer's hand
Common in the Midwestern US, certain weak hands (usually those containing three 10 cards or three 9 cards) are designated as "farmer's hands". After inspecting the hand dealt him or her, a player may call out "farmer's hand" and is then allowed to show the three cards in question and exchange them for the three unexposed cards in the kitty.

Another term used is "bottoms." Some variations allow for multiple farmer's hands to be called out, but those exchanging cards with those left behind in the kitty after the first exchange are essentially guaranteed very poor cards.


Making trump
Stick/Screw the Dealer: If the trump selection comes all the way back around to the dealer the second time, the dealer must call the trump suit. In other words, there is no option to redeal. 
Club Euchre: Whenever the upturned kitty card is suited clubs, the dealer must "pick it up" and his team must play as the makers, with clubs as trump. 

Trick-taking
Super-Euchre: If the defenders take all 5 tricks, then they score a Super-Euchre and 4 points are earned. 

Going alone
Partner's Best: When a maker "goes alone", he and his partner exchange a single card from their hands, concealed from all other players, before trick-taking begins. 
Canadian: When a player orders his partner to "pick it up", he must attempt the hand as a loner. 
Blind-Double Loner: Before the maker sees his cards, the maker calls "blind double loner". Here, the turn card is automatically trump, and the game is played by normal loner rules. If the Blind-double Loner wins all 5 tricks, 8 points are awarded to the player's team. 
Defending Alone: When a maker decides to go alone, one of the opposing players has the option of "defending alone". Here, one of the opposing players calls out "I'll defend alone" right after the loner establishes himself or herself. If the "partner's best" subvariation is invoked, then this "lone defender" also has the opportunity to exchange a single card with their partner before tricks are played. In either case, if the lone defender Euchres the loner, then his team earns 8 points. 

Scoring rituals
In Upstate NY, the scoring is almost always done with a 2 and a 3. the score is the number of pips showing. When the score is 5 or more the cards are turned into a V shape and then the score is 5 plus whatever is showing. The V is the Roman numeral for 5. 
For some players in the Midwest, when a team has nine points one places the score cards next to each other, face down. The team is now "in the barn" (also "on the corner") or "mooing". Some more casual players have been known to place the two score cards in their ears upon "entering the barn." If the team scores their tenth point then the "barn doors are opened:" the cards are flipped to show all ten pips. 
On many American college campuses, the players of a losing team which failed to earn any points at all are considered to have been "skunked" by the winning team. Sometimes, the relatively rare event of being skunked implies that the losers must perform some form of ritual penitence such as streaking the campus. 

International variations
Other variations of euchre are widely played in the southwestern counties of England, where it is common for a pub to have its own team which takes part in competitive league matches with other teams. The most common form of the game played in the UK is one where a twenty-five card deck is used; the deck consists of A-K-Q-J-10-9, with an extra card called the Benny. This card, usually a joker card or the two of spades, is the highest trump no matter which suit is called. Should this card be the one turned over by the dealer, the dealer must decide which suit to call for trumps before looking at their own hand. The bidding then continues as normal.


Extra cards
Players can also play with the extra cards 8 and 7, which adds more uncertainty to which trump cards can still be in opposing players' hands.