Some Interesting Hands

A possible double slam swing

A classic deal from Reese's "Expert Play"

1NT method leads to luckier major suit game

A laydown grand, bid by Wbridge5 and Bridge Baron

Wbridge5 demonstrates double-dummy simulation technique

Shark Bridge defends best using single-dummy technique

Jack bids 25-hcp grand slam in finals

A possible double slam swing

An highly competitive deal... with the high cards points distributed evenly to both sides and one side holding 11 hearts and the other side holding 12 spades, the 'law' estimates that one or both sides might make a slam.

⁽¹⁾ 4NT, for the minors

In the Jack versus Bridge Baron match, Jack picked up 14 Imps, making 4♠, +480 at one table and defeating 5♦x, down 5, +800 at the other table.  In the Q-Plus Bridge versus RoboBridge match, Q-Plus Bridge made 6♥ at one table and 4♠ at the other for an 18 Imp pickup.  Micro Bridge had a bye.

In the Shark Bridge versus Wbridge5 match, with the bidding shown above, at one table Shark Bridge West did not bid 'one more' in a possible double swing situation.  Both slams can be defeated with unlikely leads.  At table one, Shark Bridge West did not find the killing club lead against 6♥, leading the ♠K, and Wbridge5 has an easy +1430.  At the other table, Shark Bridge South did not find the killing diamond lead, leading the ♥Q, and giving Wbridge5 a chance to make 6♠.  Wbridge5 failed to establish a club for a diamond discard and went down one, picking up 16 Imps.

A classic deal from Reese's "Expert Play"

This hand is the only hand from the event that was intentionally inserted.  It is a hand from Reese's 1958 book, "Expert Play" and also recently appeared in the Bridge World when an author mistakenly thought he had played the hand some 50 years ago. [see p. 71 of the September 2008 Bridge World]

The theme of the hand is plan the safest way to make 4♥.  Hint: assume two trump losers and time the play to lose only one club.

At five of the six tables West declared 4♥ and at one table West declared 3♥.  Wbridge5 and Bridge Baron demonstrated the correct technique.  Micro Bridge had a bye.  When Wbridge5 declared, a diamond was led and ruffed, and a heart led to the queen and ace.  South returned a heart and Wbridge5 correctly finessed, since if trumps are 2-2 the contract is safe.  When Bridge Baron declared, a spade was led to the king, and a trump returned to the king.  When the king won, Bridge Baron abandoned trumps, and was home.  Declarer cashed 3 spades, pitching 3 clubs, played the club king and queen and ruffed the third club, eventually losing two heart tricks along with the club ace.  At all the other tables, 10 tricks were made when the defense erred.  North often discarded a club, not realizing the power of its ♣10xx.

1NT method leads to luckier major suit game

Sometimes system gets you to a luckier, albeit inferior, contract.

⁽¹⁾ both majors, maximum
⁽²⁾ transfer to spades

4♥ was played by West at five of the six tables, down one.  At four tables, the auction went 1NT - 2♣ / 2♥ - 4♥/ and at one table, Bridge Baron opened 1♦ as South, and when Jack overcalled 1NT, the auction went the same as at the other tables.  Wbridge5's bidding, shown above, got it to the only makeable game, 4♠.  4♥ is a slightly better contract.  To make game in either major, the trumps must be picked up without a loss.  When trumps are 4-1, 4♥ makes against a singleton jack or ten, while 4♠ makes only against a singleton jack.

_{A laydown grand, bid by Wbridge5 and Bridge Baron}

North-South does well to save in hearts to any level.

* 12-14 hcp

⁽¹⁾ penalty

At table one, Wbridge5 South estimated 6♣ by Micro Bridge a strong favorite and, given the favorable vulnerability, saved at 6♥.  At the other table, Wbridge5 West bid 6♦, then over 6♥, based on all the opponents' heart bids, estimated that 7♦ was a favorite.  16 Imps to Wbridge5.

Bridge Baron West might have bid 5NT over Q-Plus's 4♥, asking partner to bid the grand with two of the top three diamonds.  After key-card Blackwood, based on the opponents' heart bids, Bridge Baron estimated that the grand was a good bet.  At the other table, Bridge Baron had an easy non-vulnerable save against Q-Plus' slam. 16 imps to Bridge Baron.

In the Shark Bridge versus RoboBridge match, Shark Bridge bid 4♥ over East's 1♣ and played 4♥x, for -300.  At the other table, Shark Bridge East opened 1♣ and Shark Bridge West bid of 5♣ over South's 4♥ bid, which ended the auction. 640 to Shark Bridge, and a net of 340.

Wbridge5 demonstrates double-dummy simulation technique

In the play of a hand, one of the methods used in the 'thinking' process of a robot is a simulation technique in which the unknown hands are constructed, consistent with the bidding and play, many times over, and each construction is analyzed double-dummy.  With this in mind, watch the play unfold as Wbridge5 declared 4♥.

Against 6♥ by Wbridge5, Shark Bridge led the ♠Q. If trumps are 2-2 the slam is cold and if there is one trump loser, then there are squeeze possibilities with threats in the other three suits. A human knows that it may have to ‘best’ guess which distributions to play for, so does Wbridge5.

Wbridge5 won the ♠K in hand. A double dummy simulation⁽¹⁾ determined that the contract can be made more often by winning the king in hand than by winning the ace in dummy.  A heart was played to the ace and a heart returned to the jack and 3 — Wbridge5 ducked!  A simulation⁽²⁾, at this point, determined that the contract could always be made if hearts are 2-2, and could be made more often by ducking than by winning the king when trumps are 3-1.  East returned the ♦10.  Declarer won in dummy, and ran hearts coming down to this ending.

⁽¹⁾ The contract can always be defeated if West started with hand (a) QJ9x x xxx Kxxxx.  For any other holding, winning with the king makes the contract double-dummy, while winning with the ace loses if West started with hand (b) ♠QJxx x xxx ♣Kxxxx.

⁽²⁾  If West started with hand (a) the contract can be defeated whichever card South plays, but there are many more West holdings that ducking the heart is necessary to make the contract [e.g., if West started with hand (c) Qx x J98xx Kxxxx or hands (d) QJ9x x x(x) K(J)xxx(x)(x)] than winning the king is necessary to make the contract [e.g., if West started with hand (e) QJ9x x xxx Jxxxxx].

On the ♥4, West discards the ♠5 and Wbridge5 must now determine the remaining distribution. Wbridge5 gets it right by discarding the ♠7 from dummy. Now a spade to dummy's ace squeezed West. West blanked the ♣J to protect diamonds. Then the ♦K and ♦Q squeezed East into keeping the ♠J and the lone ♣K, so declarer pitched the ♠10 and won the last two club tricks for 1430.

Shark Bridge defends best using single-dummy technique

A further step in robotic 'thinking' is the use of single-dummy techniques, i.e., not assuming that you or the opponents will play double-dummy.  Generally, these schemes look at a position from an opponent's vantage point, and are either rule-based, as opposed to simulation based, or a combination of a double-dummy simulation with rule-based corrections.

In all three round robin matches (Wbridge5 had a bye), 4♠ was the contract, played five times by South and once by North (by Micro Bridge, playing weak NT).  Only Shark Bridge defended best.  When Shark Bridge defended against Bridge Baron South, on the lead of a club from the West hand, Shark Bridge East went up with the ♣A and underled the ♥A.  Declarer guessed wrong, playing the ♥J, and went down, losing two hearts, the ♣A and a diamond.

At the other five tables, game was made when the defense failed to give declarer a chance to go down by neither underleading the ♥A nor ducking it when declarer led a heart from the North hand.

Why did Shark Bridge get it right?  A double-dummy analysis assumes that the opponents always make the play that works, so there is no need for East to duck or underlead the ♥A, as it can never win.  Using a single-dummy technique, Shark Bridge determined there were distributions, such as the actual one, that declarer might go wrong if it underled the ♥A.  Some of the other robots use similar techniques, but still didn't get this defense right.  It is noted that jumping into an opponent's seat and using a pure single-dummy simulation technique is currently too inefficient, i.e., too time consuming.

Jack bids 25-hcp grand

Near the end of the final knockout, there was a 25-hcp grand slam. While Wbridge5 did well to reach 6♦, Jack did even better, reaching the lay-down grand using a system perfect for these hands, and picking up 11 Imps.

⁽¹⁾ 22+ total points
⁽²⁾ 1 or 4 key cards

⁽¹⁾ strong one-suiter
⁽²⁾ positive, less than 2 spades with 3+ length in the other suits
⁽³⁾ agreed diamonds as trump, 10-12 support points
⁽⁴⁾ 1 or 4 key cards
⁽⁵⁾ do you have the trump queen?
⁽⁶⁾ no!
⁽⁷⁾ I really didn't need the trump queen as partner has 3+ trumps, at most one spade and the heart ace