In Euchre, a player with a particularly good hand can raise the stakes by opting to play the hand alone. The player who selects the trump suit has this option. As soon as you indicate your intention of going alone, your partner puts his cards face-down, for this hand only, and the game becomes three-handed.
A hand with the top three trump cards (Jack of Spades, Jack of Clubs, Ace of Spades, for example) is often a sure thing for going alone, especially if you have an off-suit ace. Two of the top three trumps and an ace on the side may be enough, but you may want a little more for insurance.
The only reason for playing alone is if you have a guaranteed three tricks with a serious chance of making five tricks with your hand alone. If you make three or four tricks, you score the game the same as you do in partnership situations. But if you make all five tricks, as maker, you score 4 points.
Going alone has no real advantage unless you have a good chance to make five tricks on your own; otherwise, you simply increase the chance of a penalty without any chance of increasing the rewards. With three sure winners in your hand, you must ponder whether your remaining cards give you a chance for a clean sweep. If not, play in your partnership and hope that your partner can come through with the goods for your feeble cards.
For example, say that your partner is the dealer, the 9 of Clubs is the upcard, and you have the hand in this figure.
This hand isn’t assured of winning you three tricks, although it’s heavily favored to do so. However, if the Jack of Spades is in your partner’s hand, is one of the three cards in the muck, or is in one of your opponents’ hands without any other trump cards accompanying it (and you see three trump cards out of the seven already), you stand a fair chance of making five tricks. Still, the odds of your partner making the vital difference are almost nonexistent, because you can either win the tricks on your own or not at all. The hand in the figure above is an excellent hand to go solo on.
By contrast, consider the hand in this figure, below.
With clubs as trump, you’re almost sure to have four clear winners in your hand, but the 10 of Diamonds isn’t a favorite to win the last trick unless your opponents discard poorly; of course, their poor discarding is by no means impossible! You'd be best to go for all the tricks with my partner’s help rather than bidding alone.
Before deciding whether to go alone, here are two factors that may influence you. If the score is such that getting four points may be critical (your opponents are close to winning and you are three or four points away), that may tempt you to go for the bigger gamble. Additionally your chances of going alone and getting all five tricks are rather better on a two-suited hand than a one-suiter. With three high trumps and the A-10 in a side suit you may well find yourself taking the last two tricks, whereas the bare 10 in a side-suit is far less likely to win the last trick.