The OOLs are listed in a narrative form, giving the leader, declarer, strain (trump suit or notrump), and optimum cards. For example:
N vs W NT: any card except a ♥
N vs W ♠: any ♠; any ♦; ♣ 43
N vs W ♥: any ♠; any ♦
E vs N ♦: any ♣
E vs N ♣: any card
S vs E NT: ♠ 3; ♥ 9; ♦ KQ; any ♣
S vs E ♠: ♠ 3; ♥ 9; ♦ KQ; ♣ AK
S vs E ♥: ♠ 3; ♥ 9; ♦ KQ
W vs S ♦: ♣ 8
W vs S ♣: any card
OOL: The opening lead is the card led to the first trick by the declarer's left-hand opponent. An OOL is an opening lead that results in the maximum number of tricks for the defense. In other words, it is an opening lead that does not potentially cost a trick (or tricks).
Double-dummy play assumed: In calculating the OOLs, BridgeComposer assumes double-dummy play throughout. That is, play is assumed to proceed as if all the players could see all 52 cards and each player always plays to his or her best advantage. This may be unrealistic in some cases, but it nonetheless indicates what is possible on a given layout of the cards.
In particular, no regard is given to lead conventions. If a listed "optimal lead" would cause leader's partner to deviate from accurate defense, then it is not a practical lead in actual play.
Multiple OOLs: Usually, there are multiple OOL cards in the opening leader's hand. Sometimes, the card led has no effect on the number of tricks won; in that case, all 13 cards are deemed optimal and "any card" is displayed.
OOLs display: BridgeComposer limits the display of OOLs to the defense of the double-dummy makeable contracts.
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