It is not possible for Shark Bridge to get this wrong. Note that two rounds of diamonds must be played before running the clubs as North will discard a diamond on the fourth club. Shark Bridge now played three rounds of clubs, and, playing South to have the diamond queen, played the diamond ace and a low diamond to the ten! Now running the clubs produced the trump coup. Using double dummy techniques it is easy to get this right. South hand is well defined, with 7 or 8 spades, stiff ♥A, and likely the diamond queen.
![shark bridge 5 shark bridge 5](https://i.ytimg.com/vi/q56qIjc-BfY/maxresdefault.jpg)
An expert could see this, and so can a robot. A trump coup is needed to make the contract, and requires North to hold at least three clubs and at least two diamonds. The ♠K was returned, ruffed, and the ♥Q was cashed revealing the (bad) trump break. The lead of the ♠A, ruffed in dummy, was followed by the ♥K. Xinrui reasonably misguessed the location of the ♦Q, playing South for short diamonds, down 1 -100. This deal, from the last round robin segment helped Shark Bridge secure the final semifinal spot. Two of the four deals shown were also played in the World Team Championships. The deals here show the need for both techniques. Single dummy techniques are especially useful to correctly play certain suit combinations, e.g., A9x opposite KQTxxx or Qxx opposite AKTxx, and also useful (along with the future use of Game Theory) when the opponents’ plays are relevant. On deals where the defenders’ plays are irrelevant, the narrower declarer can determine the opponents’ hands, the easier it to play perfectly using double dummy techniques. The deals shown here are from the 2016 robot championship held alongside the recent World Bridge Games in Wroclaw, Poland, and demonstrate the strength of double dummy analysis as declarer. Because of time constraints, a single dummy algorithm uses a far lower number of sample hands than does a doubled dummy algorithm. Limited single dummy algorithms (modeled on how a human player might approach a problem) are also used.
Shark bridge 5 software#
To make decisions in the play (and at certain points in the bidding), bridge robots largely depend on double-dummy simulations (the software generates the missing hands that are consistent with the bidding and previous play), and determines, on a double dummy basis, which played card would work most often.