World robot title goes down to the last byte

The 20th Ourgame World Computer-Bridge Championship was held September 10-15, alongside the World Bridge Games in Wroclaw, Poland. The format was team play, with each team composed of four identical robots.  Eight robot teams competed for the title, starting with a 32-board round robin qualifying for the semifinal 64-board KO stage.

A very well-played hand in the last round robin session was executed by Shark Bridge (Denmark) to overtake Xinrui (China) and reach the semifinal KO stage.

Board 10
Dlr: E
Vul: Both
.
.
North
♠ T876
T743
84
♣ 932
West
♠ —
KQ92
KT73
♣ AQ854
East
East
♠ QJ
J865
AJ92
♣ KJT
South
♠ AK95432
A
Q62
♣ 76
West
Xinrui
.
6
North
Shark Bridge
.
All Pass
East
Xinrui
1
.
South
Shark Bridge
4♠
. 

Opening lead ♠A

Xinrui played South for short diamonds.  Down 1 -100.

West
Shark Bridge
.
Dbl
4NT
6
All Pass
North
Xinrui
.
Pass
Pass
Pass
.
East
Shark Bridge
1
2
5♣1
Pass
.
South
Xinrui
1♠
4♠
Pass
Dbl
.

1 one keycard

Opening lead ♠A

The lead of the ♠A, ruffed in dummy, was followed by the K. South won the ace and persisted with the ♠K, ruffed in dummy. The Q was cashed, revealing the (bad) trump break.  South was marked for long spades, stiff heart ace, and likely the diamond queen.  Playing accordingly, Shark Bridge now cashed three rounds of clubs, the diamond ace and low to the ten!  Now running the clubs produced the needed trump coup.  Note that North must hold at least 3 clubs and two diamonds and 2 rounds of diamonds must be played before cashing the fourth club, as North will discard a diamond and defeat the contract.  +1660, and 18 Imps to Shark Bridge.

Both semifinal matches were extremely close.  With both matches almost even with two boards to play, the drop of a singleton king offside would decide both matches.  In one semifinal Wbridge5 (France) needed to make 4♥ against Shark Bridge to advance to the finals.

Board 63
Dlr: S
Vul: E-W
.
.
North
♠ JT43
AQT98
AKQ
♣ A
West
♠ AQ872
732
J43
♣ K5
East
♠ 5
K2
T8765
♣ T8632
South
♠ K96
J64
92
♣ QJ974
West
Shark Bridge
.
Pass
3
All Pass
North
Wbridge5
.
2♣
3
.
East
Shark Bridge
.
2NT1
Pass
.
South
Wbridge5
Pass
Pass
4
.

1 Minors

Opening lead ♠ 5

West plays ♠Q, ♠A, ♠7 for East to ruff, and East returned a club, West playing the King. With West a passed hand, East was marked for the heart king, and East was likely 1-2-5-5, so Wbridge5 got it right and dropped the stiff K. No blood as 4 was also made by Shark Bridge at the other table, but a needed play by Wbridge5 to advance.

In the other match Bridge Baron (USA) reached 4 and needed to make the contract to advance over Micro Bridge (Japan).  With no opposing bidding, and the same plays at the first three tricks, Bridge Baron finessed for the king and went down.

The final K/O saw Wbridge5 defeat Micro Bridge in a match that came down to the last board, where Wbridge5 picked up 11 Imps to win, 162-156.

An early board in the match saw the strength of robot play.

Board 7
Dlr: S
Vul: E-W
.
.
North
♠ K9
Q872
J53
♣ QT63
West
♠ A87652
KT9
Q7
♣ K4
East
♠ QJT
J6
AKT9842
♣ 7
South
♠ 43
A543
6
♣ AJ9852
West
Micro Bridge
.
1 ♠
Pass
North
Wbridge5
.
Pass
3
East
Micro Bridge
.
2 ♦
4 ♠
South
Wbridge5
Pass
2NT1
All Pass

1 clubs and hearts

Opening lead, 3, Micro Bridge won in hand, led the spade queen but went up with the ace; a spade to the king, club to the ace, and heart 5!..Micro Bridge played low, down one, -100.

At the other table,

West
Wbridge5
.
1 ♠
2NT
4 ♣
North
Micro Bridge
.
Pass
Pass
Pass
East
Wbridge5
.
2 ♦
3 ♠
4 ♠
South
Micro Bridge
Pass
Pass
Pass
All Pass

Opening lead ♣6.

South cashed the two aces and returned the  6.  Wbridge5 won in hand, led the spade queen and overtook with the ace.  A spade return and +620. Wbridge5 +12 IMPs

Weak NT versus strong NT sometimes makes a random difference, as declarers may be different.  Micro Bridge using weak NT and Wbridge5 using strong NT, played 3NT from different sides of the table.

Board 38
Dlr: E
Vul: E-W
.
.
North
♠ A85
52
J8752
♣ T74
West
♠ Q63
K83
AT9
♣ KJ53
East
♠ JT2
AT74
K4
♣ A862
South
♠ K974
QJ96
Q63
♣ Q9

Wbridge5 opened 1 ♣, and West raised to 3NT.  Opening lead ♦ 5. Declarer ducked, won the continuation, and tried for a third heart trick.  When that didn’t materialize, down one, -100.

At the other table, Micro Bridge opened a weak NT, and West raised to 3NT. Opening lead Q.  Now Micro Bridge had the timing to establish a ninth trick, and made an overtrick,  +630.  Micro Bridge +12 IMPs

With two boards to go Micro Bridge was up 17 Imps.

Board 63
Dlr: S
Vul: N-S
.
.
North
♠ —
♥ AT62
♦ 9542
♣ KQ863
West
♠ J64
♥ Q8
♦ AT76
♣ AJ94
East
♠ KT9852
J53
♦ K3
♣ T2
South
♠ AQ73
♥ K974
♦ QJ8
♣ 75

At one table Micro Bridge went down one in 3♣-N, for -100.

West
Micro Bridge
.
Pass
3♠
North
Wbridge5
.
1
4
East
Micro Bridge
.
2 
All Pass
South
Wbridge5
1
3
.

Opening lead ♣10.  E-W cashed their 3 outside winners, ♣A, A, K.  While this was not the best order of winning the 3 outsdie winners, it appeared that there was still a trump loser, and the end of any chance for a Wbridge5 come back.  Wbridge5 now executed well to make the contract.  Wbridge5: won the club retrun; pitched the Q on the remaining high club; ruffed a club; ruffed a spade; ruffed a diamond; cashed the A; ruffed a spade; returned the 9 and overruffed East’s J with the K; and finessed West’s Q. +620 and 12 Imps.

On the last board, with Micro Bridge now up by 5 Imps, Wbridge5 needed to make its 3NT contract to take the title.

Board 64
Dlr: W
Vul: E-W
.
.
North
♠ QJT9763
Q5
Q4
♣ J5
West
♠ K
K2
A762
♣ K97642
East
♠ A852
JT87
985
♣ A8
South
♠ 4
A9643
KJT3
♣ QT3
West
Micro Bridge
1 ♣
.
Wbridge5
1♣
North
Wbridge5
3♠
.
Micro Bridge
3♠
East
Micro Bridge
All Pass
.
Wbridge5
3NT
South
Wbridge5
,
.
Micro Bridge
All Pass

At one table, Micro Bridge went down 2 in 3♠, -100.  Against 3NT by Wbridge5, as the cards lie a diamond opening lead or return when N-S first gets in is needed to defeat 3NT.  The spade lead is won by the king and a club is ducked to South.  This is the best play for Wbridge5, setting up the club suit (assuming a 3-2 break) and retaining an entry to cash the spade ace.  It had the added effect of hiding the ♣A.

South, in with the club ten, has one last chance to return a diamond, but returns a low heart, which would be right if declarer had the diamond queen, and declarer mis-guesses the heart situation, or if partner had the club ace, e.g., ♠QJ9xxx JTx xx ♣Ax. Declarer went up with the king and now had 9 tricks and the title.

Congratulations to Yves Costel, developer of Wbridge5, for his victory and Tomio and Yumiko Uchida, developers of Micro Bridge, for an exciting battle down to the last board and byte.  Kudos to all the participants for their dedication to advancing robot play and for many, developing robot software for teaching, play and entertainment.  For the 20-year history of this robot championship, go to www.computerbridge.com