Board 18 of the Mixed Teams semifinal match was also played in the 3^rd round of the robot championship.  The play shows one difference between robot play and human play.  In robot play as in human play, defense is more difficult than declarer play, but unlike in human play, the earlier in the play the more difficult it is for the robot to play best.  That is part of the reason why it is difficult for a robot defender to duck a winner early in the play in order to: give declarer a false image; possibly cut off communications; and/or give a losing option that did not exist if the trick was won.

In both the robot play and human play 6♥ was reached at three of the four tables.  In robot play the systems are more natural than in human play.  A typical auction in robot play.

After partner opened with 1 ♣ and showed 3-card heart support, West just checked for aces and went to 6♥.  RoboBridge had a similar auction. And WBridge5 reached slam after East passed then showed a strong mixed raise in clubs, then short diamonds and an ace.

The play’s the thing.  At all three robot slam tables West was declarer and the ♦K was led.  All the declarers won, ruffed a diamond, then either led the ♣Q (two tables) or played ♠A, spade ruff, diamond ruff, ♣Q.  In all cases North won the King and returned a trump or diamond.  The declarers had no trouble making 12 tricks with 5 hearts, 4 clubs, 2 aces, and a diamond ruff.

In the human play only Voldoriere-Avon against Mahmood-Michielsen stayed out of slam.  The auctions were quite different at the three tables that reached slam with East as declarer twice.  At all of these three tables North ducked the first club. Against Auken-Welland, with Auken (East declarer) a heart was led, won by declarer and the ♣Q led and ducked.  Auken followed with a club to the ace and club return.  A spade return followed and declarer had no choice but to take the finesse (North had not bid as the auction started 1♣-P-1♠*-P).  Then ♦A diamond ruff, ♠A pitching a diamond, spade ruff, diamond ruff, and 12 tricks.  In the other match, at one table a heart was led and when the ♣Q was ducked, declarer repeated the finesse trying to pin the ♣10.  North won and gave partner a club ruff.  Down one.  At the other table West was declarer at 6♥, with hearts mentioned for the first time at the six level after East opened a Precision 2♣, and showed 5-3-1-5.  After ♦K to the ace, declarer led a small club toward dummy and won the queen when North ducked. Now ♣A and then ♠J passed around.  Even if it lost the club can be pitched on the ♠A. A diamond ruff followed.  It looks as if declare will make 13 tricks but there is a trump promotion at the end.