Check before you blame the robots! (English Bridge Union)

Article written by Christophe Grosset and published in the magazine the English Bridge Union (February 2017).

Whether your partner is a human being or a robot, the temptation to blame him for bad results is sometimes strong. Funbridge now offers the option to check if you are actually better than your partner on the platform by letting you challenge Argine, the robot, for as many 5-board matches as you want. Playing against this robot is proving much more challenging than most people would think, at the moment Argine has 80% victories, 2% draws and 18% losses against users; can you do better?

Here is a board on which you have a chance to
beat Argine:

K J 9 8 5 4  10  7 6 2  Q 10 9

 
South opens 2♠, and, being down in the match you simply decide to raise to slam with the North hand. It is probably not a good long term bet to leap to slam with this hand, but an opportunity to get imps back might not come up again in a 5-board challenge.

West leads the ♦10, and it is time to stop in order to choose a line and carefully plan the play.

There are three potential losers, one in spades and two in diamonds. In order to make the contract, declarer has to assume that they will manage to play the spades for no losers and then they need to get rid of one diamond loser.

There are two options to limit your diamond losers to one. The first is to discard one of dummy’s diamonds on the ♣Q and then to ruff one in dummy. This simple line will work every time the
spades are 2-2, as this is the percentage play for no spade losers. It seems like a good plan.

The second option would be to establish dummy’s fifth heart by ruffing them out. This line seems inferior to the previous one as it requires the hearts to split 4-3 on top of finding the spades.

When playing my challenge on Funbridge, I followed this reasoning, took the ♦A, played the ♠A and saw the queen drop in East … I realised that I had made a critical mistake already by failing to
foresee this possibility when I made my game plan at trick one. Can you see why?

Here is what happened after I saw the ♠Q. I could not afford to play another spade, so I played the ♣A and ♣K, the ♥A, a heart ruff, the ♣Q pitching a diamond and a diamond. This was the position when East won the ♦Q:

6 2  J 5 4  –  –

10 7  K  9 5  –

–  Q 9  K  8 6

K J 9 8  –  7  –

 
He played back a club which created a trump promotion, guaranteeing West one trump trick.

To avoid this, declarer had to duck the diamond at trick one! By doing so, after following the same
line, South would be on lead in the position shown above, able to safely ruff a diamond before taking the last four tricks with his high spades.

Would you have beaten Argine on this deal?