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Contemporary Development With Functional Programming

The Schnapsen Log

August 17, 2012

Tempo (solution)

Martin Tompa

It’s often the case that close battles with no marriages declared come down to winning the last trick. When you are in such a situation, you should be thinking about how to win the last trick starting at trick 5 or 6.

An easy way to see that you will need to take the last trick to win today’s deal is by adding up all the trick points you could possibly collect (♣AQ and at best ♣K and J with Peter’s KJ) and seeing that this optimistic total would still only bring you to 64 points.

Often, in order to win the last trick, you want to preserve the winners in your hand and lead out the losers. The typical pattern will be that you and your opponent will alternate winning a trick and leading out a loser.

In today’s deal, that suggests leading Q. Let’s see what happens if you do that. Peter will win A. One way he can continue is to follow the edict of playing a loser, J, forcing you to trump. This would lead to the following position with you on lead:

Peter: (43 points)
A
K
♣ Q

You: (42 points)


♣ AKJ

From here there is nothing you can do to avoid handing Peter the last two tricks.

Let’s go back to trick 6 and investigate your alternatives to leading Q. You could consider leading J, but this seems unlikely to succeed, since you’d really like J to be one of your winners. It’s not hard to see that leading J won’t work: Peter will return ♣Q and you won’t be able to avoid handing him the last trick with your Q.

The only other possibility for your lead at trick 6 is to cash ♣A and then force him to trump your loser ♣J next. Here is the position that would result, with Peter on lead:

Peter: (42 points)

AKJ
♣ —

You: (52 points)
J
Q
♣ K

Peter has no choice but to cash A and then lead another heart, and you will win the last two tricks and the deal. (Notice that this winning diagrammed position is the mirror image of the previous losing diagrammed position.)

This successful plan of leading clubs makes some intuitive sense, because you want to force Peter to trump so that you gain trump control. It’s another example of the forcing defense. But there is more to today’s deal than just another forcing defense. To illustrate what I mean, suppose we make a tiny change in Peter’s hand by substituting J for J. Here is what the position would be after he trumps and gains the lead:

Peter: (42 points)

AK
♣ —
J

You: (52 points)
J
Q
♣ K

From this position, the normal pattern of trading leads would continue: Peter leads his losing J for you to trump, and you cannot prevent him from taking the last trick with A.

Now go back to the real position at trick 8 diagrammed above, where all Peter has left are his three hearts. The interesting thing about this position is that Peter is compelled to cash a winner rather than leading a loser, disrupting the normal pattern of trading leads. This disruption of the pattern is key to his loss of the last trick, because he is coerced to use up a precious winner instead of retaining it to regain the lead later. Bridge players would say that Peter “loses a tempo” when he is forced to cash his A, referring to the disruption of the pattern of trading leads. Peter is endplayed at trick 8 by a form of endplay we have not yet seen, one that is particular to the struggle for the last trick. I will call it a tempo endplay.

Let’s come full circle and return to our first idea of leading Q at trick 6. One way of seeing now that this is a bad idea is that it relieves Peter of later losing a tempo, by letting him use his A to gain the lead right away. You want to leave that A alone, and it will come back to disrupt your opponent’s tempo later.

© 2012 Martin Tompa. All rights reserved.


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About the Author

Martin Tompa

Martin Tompa (tompa@psellos.com)

I am a Professor of Computer Science & Engineering at the University of Washington, where I teach discrete mathematics, logic, probability, design and analysis of algorithms, and other related courses. I have always loved playing games. Games are great tools for learning to think logically but, more important, seem to me an integral part of happy family or social life. I will be delighted if game-players, parents, teachers, and students find this series fun and useful.

My excitement about Schnapsen was rekindled by playing against an iPhone program called Master Schnapsen/66 written by two friends at Psellos. Set to play at its “Master” level of difficulty, this program is one of the two most formidable opponents I have found. It comes up with surprising and brilliant plays, and I have learned an enormous amount of Schnapsen strategy by playing with it. Nearly every deal in this Schnapsen Log arose during those hours of playing with Master Schnapsen/66.

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