4 (two teams, partners sit across from each other)
One euchre deck (one standard deck with 2s through 8s removed, and the 5s set aside for scoring)
The game is over when one team gets at least 10 points.
There are lots of variations on dealing, but the point is to deal all the cards going around twice. Some tournaments require "standard dealing", which is: 3 cards to the person to the left of the dealer, then 2 cards, then 3, then 2 to the dealer; then 2 to the person to the left of the dealer, then 3, then 2, then 3. No matter how you deal, each person should have 5 cards, and there should be 4 cards left over.
After the dealer deals the cards, there should be four cards left. The top card of the four cards left is turned up. It is important to catch any misdeals (count the four cards!) before you turn the card up; if a misdeal is caught after the card is turned up, the deal passes to the left; if a misdeal is caught before the card is turned up, the cards are collected and re-dealt by the same player (see "Misdeal rules" in the Variations section).
The suit of the card that is turned up is offered for trump.
A trump suit means a suit that beats the other suits when cards are played. For example, if hearts are trump, then a heart will always beat a non heart. There is no value to other suits other than trump; one non trump suit does not beat another non trump suit.
In euchre, the value of cards for trump is (highest first):
For the non trump suits, the normal order is used (A-K-Q-J-10-9). Note that the Jack of the same color as trump (left bower) is considered to be trump for that hand.
Hearts is trump.
The order from highest to lowest of trump cards is:
J♥ J♦ A♥ K♥ Q♥ 10♥ 9♥
The order from highest to lowest of diamonds is:
A♦ K♦ Q♦ 10♦ 9♦
The jack of diamonds is considered a heart for this hand.
When cards are played, you must follow suit (play the same suit as the first card played) if you have a card (or cards) in that suit. If you do not have cards in that suit, you may play trump (to try and take the trick), or you may play another suit (and waste the card).
The suit of the card that is turned up is offered for trump. The person to the left of the dealer decides if they want that suit to be trump. If they do, they order the dealer to pick up the card (the dealer will discard another one, to get back to 5 cards), and trump is made. If they do not, they say "pass". If they pass, the next person in clockwise order can choose. If all pass, they dealer has the option to make that suit trump by taking the card into his hand and discarding one, or passing by turning the card over.
If the dealer turns over the card, then the person to the left of the dealer now has the option to call any other suit trump if they wish, or they may pass again (they cannot call the suit of the card that was turned over). If all three players pass a second time, then the dealer may call a trump suit, or if he chooses to pass, the cards are collected, and the deal moves to the next person to the left, with no points scored for either team (see "Screw The Dealer" in the Variations section).
The two partners work together to take tricks. If the team that calls trump collects 3 or 4 tricks, they are given one point; if they collect all 5 tricks, they are given two points. If the team that calls trump does not collect at least 3 tricks, the opposing team is given 2 points (this is called "euchering your opponent").
When declaring trump, a person may choose to "go alone". This means that they believe they can get the required tricks without their partner's assistance. If they do get all 5 tricks, they are given 4 points instead of 2 (see "Cross Corner Alone" in the Variations section).
Once trump is set, the person to the left of the dealer plays first. If that person is not playing because someone is going alone, then the first playing player to the left of the dealer plays first (see "Leading Alone" in the Variations section). The player will play a single card. Each player must follow suit if they have it, or they may choose to play trump or an off suit. A trump card will beat a non-trump card.
The winning team collects the trick, and the person who played the card that won the trick is the person who leads for the next trick. The hand is over when all 5 tricks have been played.
Each team has two fives which are used for scoring. In the beginning of play, place one five face up, then the other five face down on top of it. As you mark the first five points, expose the five pips on the bottom five. When you get five points, flip the top card over, and expose the bottom five pips for six through ten.
There are quite a few possible variants on how Euchre is played. Personally, we always play "First Black Jack Deals", and occasionally play "Screw the Dealer".
"First Black Jack Deals"
Someone takes the deck and shuffles the cards, then deals the cards one at a time, face up, to each player, starting with the first player to the left of the person dealing, and moving clockwise. You stop when the first black jack is turned up; this person is the first dealer.
"Farmer's Hand" (or "No Ace, No Face") -- if your hand contains all 9s and 10s, you can declare a misdeal before bidding for trump.
"Ace, No Face" -- if your hand contains one ace, and the rest 9s and 10s, you can declare a misdeal before bidding for trump.
"Stick the Dealer"
When you play with this variant, the dealer is not allowed to pass on the second time around. He must call a trump suit (other than the suit that was turned over, of course).
"Cross Corner Alone"
When a person chooses to go alone, one of the other team members may also choose to go alone. If the opposing alone person manages to collect all 5 tricks, they will score 4 points instead of 2.
Some people play that you are not allowed to lead if you are playing alone (except for "cross corner alone", where the opposing alone person will always get to lead). This adds an element of difficult to going alone.
"Alone, Partner's Best"
When you go alone, you can call "partner's best". The person going alone discards one card to the dead pile; their partner slides their best card across the table to them face down, and they put it in their hand.