The Rule and the Scoring
Call trump, then say you are going alone. Your partner turns their cards face down and sits out. You play your five cards against the opponents' ten, and each trick has three cards in it instead of four. Taking all five is a march, and the march is the only thing going alone changes.
- All five tricks alone: four points. The same march with your partner in is two.
- Three or four tricks: one point, alone or not.
- Fewer than three: euchred. Two points to the opponents, alone or not.
Three of the four outcomes pay the same either way. Only the march moves. So the question is not whether you can take all five tricks, it is whether your partner was going to help. If their hand was never going to matter, the extra two points are free. If they were supplying your third trick, sitting them down turns a routine point into a real chance of losing two.
Hands Worth Calling
Seven cards are trump: the six in the suit plus the left bower. Two holdings sweep no matter how the deck fell.
- R + L + A + K of trump plus any off-suit ace. Lead the four trump. At most three are out, all lower, and following suit is mandatory, so four rounds strip both opponents and your ace takes the fifth.
- R + L + A + K + Q of trump. You hold the top five trump. They hold the 10 and the 9.
Nothing else is proof against every distribution, but one test does most of the remaining work: do you hold the top three trump? R + L + A cannot be beaten and you will always get to play all three. Worst case you follow suit twice, trump in on the third trick, then lead trump from there. Three tricks nobody can take means you cannot be euchred, so the loner costs you nothing: the floor is the same point the partnership call was going to score. Passing on that hand is the mistake, not calling it.
R + L + A plus two off-suit aces is the classic loner. The trump tricks are certain, the aces are not, because four trump are still out and an opponent holding three or four of them will run short of a suit and trump an ace. Call it anyway. R + L + A + K plus a low side card is four certain tricks and a gamble on the fifth, lost only if one of the two cards the opponents kept back outranks your side card.
What does not qualify is both bowers and nothing behind them. R + L + 9 of trump with two low side cards is two locked tricks and nothing certain after. It can still be euchred and it will almost never march.
Which Seat You Are In
The opening lead goes to the dealer's left and skips the player who sat down, so only first seat leads its own loner. From second or third seat a defender leads and you play second of the three; as dealer, a defender leads and you play last.
First seat and the dealer are the good seats, for opposite reasons. Leading strips trump before anyone can attack a suit you are thin in; playing last lets you take each trick with the smallest card that works. Second and third seat are the weak spots, because a defender picks the opening suit and a good one picks their longest, so their partner can trump in.
First seat carries a cost of its own. Going alone in the first round means ordering the up-card into an opposing dealer's hand, so you are handing a trump to someone you now have to beat by yourself. A first-round loner from first seat should be strong enough that it does not matter.
Score Situations
- Your team at six or seven: the best time to go alone. Four points ends the game; a partnership march does not.
- Your team at eight: a partnership march already wins it. The loner adds only risk.
- Your team at nine: one point wins. Keep your partner.
- Opponents at nine: same answer, better reason. Getting euchred hands them the game, and your partner is what stops a euchre.
Defending Against a Loner
A loner scores four for the sweep and one for four tricks, so the single trick you steal is worth three points. Your job is not to euchre them, it is to take one trick.
Never lead trump against a loner, not even a bower. It does their work for them and strips your side of the only thing that beats their off-suit winners. Lead low from your longest off-suit instead: the more of a suit you hold, the fewer are left for everyone else, so your partner is likelier to be void in it and able to trump in.
Hold a lone off-suit ace back rather than leading it. A loner is short somewhere by definition, since three or four of their five cards are trump, so an ace led early stands a real chance of being trumped. Once they have run their trump out it is safe, and it takes the trick if they have to lead that suit at the end. The exception is holding two off-suit aces: use one while it is still live, so you are not squeezed out of it later.
See Also
The bid comes first: see how to call trump. For the full scoring table see the euchre rules, and Learning Mode narrates the bots' reasoning if you want to watch loner calls get made and defended.