Life So Short, the Craft So Long to Learn

The Schnapsen Log

September 26, 2012

X-ray Vision (solution)

Martin Tompa

Which card lies face-down on the table? You should be able to see through the back of this card as though you have x-ray vision.

Katharina just picked up the face-up K, but she didn’t end the deal by declaring the royal marriage. You should have absolutely no doubt that the face-down card remaining in the stock is the mate, Q. This inference is wonderful news for you, because it means that you will draw an important trump from the stock if you win this trick. And, of course, you cannot afford to duck this trick, because that would hand Katharina the royal marriage.

So, you trump her K lead with A, leaving you on lead in this position:

Katharina: (51 points)
♣ —

You: (28 points)
♣ K

Now what? You cannot avoid giving up a diamond trick at some point, which will give Katharina 64 trick points. This means that you must avoid yielding any trump trick to her. The only way to avoid that is to endplay her so that she is forced to open up the trump suit herself. This in turn means that you have to eliminate her K before the endplay, or else she will have this exit card in her hand to lead instead of a trump when she is on lead. Are you also concerned about eliminating her T as an exit card? We will see in a moment that you needn’t worry about that.

So, then, first cash A, and then throw Katharina in with J, so that she is on lead in this position:

Katharina: (64 points)

♣ —

You: (43 points)

♣ K

Can Katharina now exit with T? No, because you would trump that with Q for 56 trick points, and then cash T to give you enough. All she can do is lead one of those trumps, which allows you to pull the other and then cash your ♣K to win the deal.

This deal is a nice combination of counterforce and elimination plays, the first time we have seen those two plays combined. The counterforce is because she cannot afford to force you with T, the elimination because you have eliminated her other safe exits and thrown her in to lead away from her vulnerable trump holding.

But the important new lesson in today’s deal is the inference of Q as the mystery card remaining in the stock. Particularly when only one card remains face-down in the stock, it is very important to consider whether your opponent’s play has narrowed down the possibilities for what that card is.

© 2012 Martin Tompa. All rights reserved.


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About the Author

Martin Tompa

Martin Tompa (

I am a Professor of Computer Science & Engineering at the University of Washington, where I teach discrete mathematics, probability and statistics, design and analysis of algorithms, and other related courses. I have always loved playing games. Games are great tools for learning to think logically and are a wonderful component of happy family or social life.

Read about Winning Schnapsen, the very first and definitive book on the winning strategy for this fascinating game.


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