March 2020 - 28

Bridge Bots Battle in San Francisco
The 23rd annual World ComputerBridge Championship crowned a new
champion. Micro Bridge, developed in
Japan, emerged the winner after six
days of play during the San Francisco
North American Bridge Championships.
The seven entries developed by international individuals or teams were:
⦁ Meadowlark Bridge (U.S.)
⦁ Micro Bridge (Japan)
⦁ Q-Plus Bridge (Germany)
⦁ RoboBridge (Netherlands)
⦁ Synrey Bridge - runner-up for the
past two years (China)
⦁ TCS BridgeBot (India)
⦁ Wbridge5 - three-time defending
champion (France)
Each entry played as a team of four
identical bridge bots.
The round-robin phase ended with
the top four bot teams advancing to the
64-board semifinal knockout stage,
where Synrey Bridge defeated Q-Plus
Bridge, 175-133, and Micro Bridge
ousted tournament favorite Wbridge5,
182-140.
Micro Bridge overwhelmed Synrey
Bridge in the final, 120-35. A big win
for the Micro Bridge team, having lost
the past five years in their semifinal or
final match.
An interesting play problem in the
third quarter of the semifinals demonstrates some good bot "thinking" by
Q-Plus Bridge.
Dlr: North ♠ K J 10 2
Vul: E-W ♥ 10
Board 9
♦Q32
♣ Q J 10 5 3
♠Q54
♠96
♥Q95
♥A87642
♦ 10 6 4
♦K985
♣A864
♣9
♠A873
♥KJ3
♦AJ7
♣K72

28 Bridge Bulletin March 2020

West North
Synrey Q-Plus
Q-Plus Synrey
Pass
Pass
2♣
Pass
4♠

East
Synrey
Q-Plus
Pass
Pass
All Pass

South
Q-Plus
Synrey
1NT
2♠

Opening lead: ♦4 by Synrey, ♦6 by
Q-Plus Bridge
Q-Plus Bridge won the ♦J at trick
one. While there are a number of lines
of play, one possibility is to pull trumps
by taking the trump finesse toward
the safe hand, that is, toward the hand
that has the ♦K. If that finesse loses,
declarer may still have time to set up
the clubs for a diamond pitch, as the
defense may not be able to set up a
diamond winner in time. Even if the
finesse is taken through West and loses
to East's queen, barring a quick club
ruff, a heart return may set up a heart
winner for declarer to make its contract.
Generally a robot's analysis would
result in taking the trump finesse
equally each way, as it would not place
the ♦K in one hand more than the
other. However, Q-Plus Bridge adds to
its "thinking" process the tendency of
a defender, given the auction, to choose
a safe lead, so hands with the ♦K
and without a heart or club honor are
reduced in probability. With East more
likely to hold the ♦K, Q-Plus Bridge
took the trump finesse against West:
plus 450.
Synrey Bridge fails to take inference
from the lead, and finessed through
East, losing to the ♠Q. A diamond
return set the contract one: minus 50
and 11 IMPs to Q-Plus Bridge.
In the other match, with the same
auction, Micro Bridge led the ♦4
against Wbridge5's 4♠ contract.
Wbridge5 took the losing trump finesse, and with a diamond return, was
down one, minus 50.
At the other table, North-South
reached 4♠ after WBridge5 opened

BY AL LEVY

2♥ as East. West led a heart to East's
ace; East returned a club to partner's ace for a club ruff. Micro Bridge
declarer won the diamond return and
played three rounds of trump, finessing
against West: plus 420 and 10 IMPs to
Micro Bridge.
Micro Bridge's good decisions on
slams helped it to victory. Finding the
best suit for slam in the final netted
Micro Bridge 14 IMPs on this deal:
Dlr: South ♠ A 10
Vul: N-S ♥ 10 9 8 5 2
♦874
♣K64
♠K843
♠Q952
♥4
♥AKQ
♦AKQ2
♦ J 10 6 5 3
♣A832
♣J
♠J76
♥J763
♦9
♣ Q 10 9 7 5
West North
Micro Synrey

East
Micro

1♦
3♠

1♠
6♦

Pass
Pass

South
Synrey
Pass
Pass
All Pass

At both tables, with the same first
three bids, the 4-4 spade fit was found.
Micro Bridge made the better slam
decision, playing in 6♦, the solid ninecard fit, while Synrey Bridge played in
6♠, the less robust eight-card fit. 6♦
was cold on any lead (Synrey actually
led the ♠A), while 6♠ went down on
the diamond ruff.
The championship was sponsored
by the ACBL and World Bridge Federation, and run by organizer Al Levy. For
all the results of this year's event, as
well as past championship results and
interesting articles on bot play, go to
bridgebotchampionship.com.
◾
http://www.bridgebotchampionship.com
March 2020

Table of Contents for the Digital Edition of March 2020
