Understanding Card Marks

Central to using Deep Finesse is understanding why cards are marked with , , , or . Try running one of the demo deals and you will see that at each player's turn, all legally playable cards are labeled with one of these symbols. A card labeled with a is termed a "Winner" because playing it results in a winning position. Similarly, an card is a "Loser" because playing it results in a losing position. A winning position for the declarer means the contract can make against any defense. A winning position for the defenders means the contract can be set against any line of declarer play.

and marks indicate plays that make or set a contract exactly, assuming subsequent perfect play by both sides. and marks indicate plays that make over or under tricks. For declarer, means that card can make the contract with overtricks; for the defence, the contract can be set with undertricks. The reverse logic applies to . You can think of as being an even better play than and an even worse play than .

As long as the side with the winning position continues to make sound plays, they are assured of reaching their objective - making or setting the contract. Only by playing cards labeled with a or can one reach or maintain a winning position. Choosing a losing play when winning plays are otherwise available is a blunder, and the winning position will shift to the other team. Of course, the team that is stuck in a losing position will have nothing but losing plays to choose from unless their opponents blunder at some point.

In addition to the above card marks, a is attached to the card that has won the current trick. Don't confuse a "winning play" with "winning a trick." As all bridge players know, sometimes deliberately losing a trick (ducking) is the only way to make or set a hand. A card play that wins the current trick might be a losing play for the contract as a whole. Similarly, a card play that deliberately loses the trick might be the only winning play available.

When you change the line of play by clicking on a new card, Deep Finesse will automatically re-compute and re-label the winning and losing plays from that point onward. If South leads a winning card to a certain trick, for example, then West will have nothing but losing plays available to him. If you change South's lead by clicking on a losing card in his hand, winning plays will suddenly appear in West's hand.

Deep Finesse normally displays card marks on all legal plays. You can turn off the card marks by clicking the toggles in the lower left of the screen. And finally, sometimes you may see cards labeled with a . That means Deep Finesse is still evaluating that card play. It will be converted to one of the concrete marks once analysis is complete. For more, see Understanding Hand Analysis.