As I said in the opening page, what you do on the fourth trick could determine the outcome of the hand. Will you make one point, two points, euchre your opponents, or euchre yourself. Different situations require vastly different plays. Still, there are some general guidelines.
West is the dealer and turns up the queen of diamonds. Everyone passes and the dealer picks the queen. This gives him a three trump, two-suited hand.
North starts the hand by leading the ace of spades. East plays the jack, south shows void and West trumps in with the 10. The calling team has their first trick with one trump played.
Having taken the first trick, West leads back the ace of hearts. North assumes that because they didn't lead the right, they don't have it. North decides to take a chance, split their left-king combination, and trump with the king. The king takes the trick. This gives N/S one a trick. Two trump played.
As a side note, look at what would have happened if our page on how to play the three trump two-suited hand with an off-suit ace had been read. Here the correct lead was the middle trump.
North leads the jack of clubs. East follows suit with the queen and South plays the ace. West trumps in with the queen taking their second trick. Now three trump are played.
North quickly reviews what he knows up to this point. The maker most likely doesn't have the right or he would have led it. East seat doesn't have it either or he would have over-trumped the king on the second trick. His partner(S) was the only one to follow the first heart lead. North trumps using the left. This leaves his partner in South holding the right for the last trick and completing the euchre.
Now, look what happens North lets the trick go by and hopes South can take it. The bidders make their point. You and your partner are left sitting with both bowers.
Remember, maker never led the right; it was most likely because he didn't have it. In circumstances such as this, you have to consider the possibility that your partner may have it.