When naming trump, most players start out with a general thought as to how they are to play the hand. As the hand progressives, there could be times when a strategy change becomes necessary. These are the hands where you know there are still trump out against you. Those trump may result in you being euchred. Because it takes a trump to beat an off suit ace, leading an ace may be an effective way to eliminate them. This tactic may be used anytime during the hand. It works best after one round of trump has been pulled and, as the maker, you're concerned about any remaining trump in your opponent's hands..
The dealer is in North and bidding is passed back to him. He looks at his hand and thinks, let's see, I'm holding three trump, an ace in diamonds and I'm void in clubs. This should be an easy point.
East seat starts the hand by leading the ace of spades. South follows using the 9. West seat throws off a useless 9 of diamonds and the maker(N) has to follow suit and plays the jack. The ace of spades is good and now the opponents have one trick.
After taking the first trick, East leads back the king of spades. Again South has to follow suit and plays the ten. West throws away a second diamond and the maker(N) takes the trick using the trump 9. One trump been played and both teams now have a trick apiece.
Suddenly the hand is not looking as strong as it once was. Only one trump has been played, the right plus the ace of trump is still out. By leading the left, the maker(N) is hoping all the big trump fall at the same time. That would be ideal, but it's not happening this time. East shows void, his partner(S) plays the queen, West plays the trump 10. Now four trump have been played and bidding team is two tricks in.
The bidding team still needs one last trick to make their point. The maker knows that there are still two trump possibly out against him, the right and the ace. If he leads trump and the opponents hold another boss card he's most likely euchred. The only hope would be if they lead back a diamond. He decides to use the ace of diamonds to 'go fishing'. This will give him the best chance of making the point as: 1) the ace walks or 2) there is one trump buried and the other will be used to take the ace.
Everything goes as planned and the team makes their point.