Problem thread.

[han]

I thought it might be a nice idea to have a thread with play problems. I hope many of you will post some good problems here. I suggest the following guidelines:

 

- Never take a problem that appears elsewhere unless you have permission.

 

- Intermediate players should have a shot at solving the problems (intentionally a vague rule).

 

- There should be a clear solution.

 

- Add the solution in hidden text below the problem.

 

Please don't respond to problems in this thread. If you think that a suggested solution is not clearly correct then you can start a new thread or contact the poster. The poster will be able to edit his or her post.

[han]

Which Finesse?

 

[hv=d=w&v=n&w=s2hkqj1087daj74c32&e=saq4ha96543dk2ca5]266|100|Scoring: IMP

1H - 4NT

5D - 7H

[/hv]

 

Partner has once again put you in a grand slam, but this one has more chances than usual. North leads a club. How should you try to make your contract?

 

Hidden solution:

 

 

 

This is a common theme, you should try to combine your chances in spades and diamonds. Win the club, pull the outstanding trump and play king and ace of diamonds and ruff a diamond. If the queen of diamonds has appeared you can pitch a club on your jack of diamonds. If not then you still have the spade finesse.

 

 

[ralph23]

 

Diamonds will split 4-3 (a priori) about 62% of the time. 3/7th of those splits, the Queen will be in the tripleton hand. So you will succeed in ruffing out the tripleton Queen 3/7th of 62% of the time, or about 27%.

 

Diamonds will split 6-1 in 6.78% of the cases, a priori. One-seventh of the time, the singleton will be the Queen; that comes to about 0.95%.

 

And they will split 5-2, a priori, 30.5% of the time. Question: How many times out of a hundred will the doubleton, selected from 7 cards overall {a 5-2 split}, contain the Queen? If N is the Answer (expressed as a percentage), then N times 30.5% = X.

 

The remaining (100 - 27 - 0.95 - X) = Y% of the time, you will have to try the spade finesse, so your overall a priori odds are about (100 - Y)% plus (half of Y)%

 

You can try to increase your odds by playing off a couple of unnecessary rounds of trumps, of course. Sometimes a poor player may actually discard a diamond from Qxxx, and it may become subject to being ruffed out, when it wasn't originally ..... or your LHO may discard a couple of diamonds from xxx, something he probably wouldn't do from Qxxx ... but as always be wary of diamond discards as a clue to the holder of the Queen. It's amazing how poorly some players may discard!

 

Edited September 4, 2007 by ralph23

[jdonn]

RALPH!!!

Please don't respond to problems in this thread.

[ralph23]

This one came up on BBO the other day. I was declarer (North) at 6♠.

 

[hv=d=n&v=b&n=sakqj743h98djcat7&s=st862hak6da95cq95]133|200|Scoring: IMP[/hv]

 

A ♦ was led, the Ace was taken in dummy and trumps were 1-1.

 

1. What is the only problem suit ?

2. Is there a 100% line now that trumps have been drawn?

 

 

Clearly clubs is the only problem suit.

 

Just strip out the red suits by ruffing any heart or diamond losers and end up in dummy to lead a club.

 

You have 4 of the top 6 clubs, lacking only the King and the Jack, so as long as you don't lose a trick to both of those, you are making. There are several ways to play it, but a simple way is lead a club from dummy, and if a big one appears on your right, take the Ace; if a small one appears, then finesse, lose it, and you have endplayed your opponent.

 

Can you convince yourself that unless you strip out the red suits first, there is some configuration of cards that will allow you to be defeated?

 

[han]

Here is another well-known idea:

 

[hv=d=w&v=n&w=sa53ha53daq5cq532&e=skq4hkq4d742cj1094]266|100|Scoring: IMP

1NT - 3NT[/hv]

 

North leads a diamond to south's king. Plan the play.

 

Hidden solution:

 

 

If diamonds split 4-3 then you will make the contract by setting up club tricks. But if north has 5 diamonds then you have to be careful. If you win the first trick and play on clubs, south could win and return a diamond. Ducking now wouldn't help because north would overtake and play a third diamond. If north has the missing club honor then you go down, losing 3 diamonds and 2 clubs before you can take your tricks.

 

You can guard against this by ducking the first trick. You will make 1 tricks as long as the opponent with 5+ diamonds doesn't have both club honors.

 

[ralph23]

♣♦♥♠

 

[hv=d=w&v=n&n=s654ht62d65ckqjt9&s=sak2hk43daq43c432]133|200|Scoring: IMP[/hv]

 

After West opens a weak 2♥, you find yourself (South) in 3nt.

 

West leads the Queen of ♥, you play low from the board, and East surprises you by producing the ♥Ace. :D How do you proceed ?

 

 

If you think West has a 6-card suit -- let's assume it -- then what will happen if you waste a low heart at trick one? East will return a diamond, say, you'll try the Queen and win, and you'll start on clubs. Somone has 3-4 to the Ace, and they take the third ♣ round, getting the count from his p ....

 

Edited September 4, 2007 by ralph23

[the hog]

This one came up on BBO the other day. I was declarer (North) at 6♠.

 

[hv=d=n&v=b&n=sakqj743h98djcat7&s=st862hak6da95cq95]133|200|Scoring: IMP[/hv]

 

A ♦ was led, the Ace was taken in dummy and trumps were 1-1.

 

1. What is the only problem suit ?

2. Is there a 100% line now that trumps have been drawn?

 

 

Clearly clubs is the only problem suit.

 

Just strip out the red suits by ruffing any heart or diamond losers and end up in dummy to lead a club.

 

You have 4 of the top 6 clubs, lacking only the King and the Jack, so as long as you don't lose a trick to both of those, you are making. There are several ways to play it, but a simple way is lead a club from dummy, and if a big one appears on your right, take the Ace; if a small one appears, then finesse, lose it, and you have endplayed your opponent.

 

Can you convince yourself that unless you strip out the red suits first, there is some configuration of cards that will allow you to be defeated?

Did this really come up Ralph? This is a well known "book hand".

[ralph23]

This one came up on BBO the other day. I was declarer (North) at 6♠.

 

<!-- NORTHSOUTH begin --><table border=1> <tr> <td> <table> <tr> <td>Dealer:</td> <td> North </td> </tr> <tr> <td>Vul:</td> <td> Both </td> </tr> <tr> <td>Scoring:</td> <td> IMP </td> </tr> </table> </td> <td> <table border='1'> <tr> <th> <table> <tr> <th class='spades'>♠</th> <td> AKQJ743 </td> </tr> <tr> <th class='hearts'>♥</th> <td> 98 </td> </tr> <tr> <th class='diamonds'>♦</th> <td> J </td> </tr> <tr> <th class='clubs'>♣</th> <td> AT7 </td> </tr> </table> </th> </tr> <tr> <th> <table> <tr> <th class='spades'>♠</th> <td> T862 </td> </tr> <tr> <th class='hearts'>♥</th> <td> AK6 </td> </tr> <tr> <th class='diamonds'>♦</th> <td> A95 </td> </tr> <tr> <th class='clubs'>♣</th> <td> Q95 </td> </tr> </table> </th> </tr> </table> </td> <td>  </td> </tr> </table><!-- NORTHSOUTH end -->

 

A ♦ was led, the Ace was taken in dummy and trumps were 1-1.

 

1.   What is the only problem suit ?

2.   Is there a 100% line now that trumps have been drawn?

 

 

Clearly clubs is the only problem suit.

 

Just strip out the red suits by ruffing any heart or diamond losers and end up in dummy to lead a club.

 

You have 4 of the top 6 clubs, lacking only the King and the Jack, so as long as you don't lose a trick to both of those, you are making. There are several ways to play it, but a simple way is lead a club from dummy, and if a big one appears on your right, take the Ace; if a small one appears, then finesse, lose it, and you have endplayed your opponent.

 

Can you convince yourself that unless you strip out the red suits first, there is some configuration of cards that will allow you to be defeated? 

Did this really come up Ralph? This is a well known "book hand".

Are you calling me a liar? Sure sounds like it.

 

What's the book ? And the page. I'd like to see the hand duplicated somewhere other than BBO, given that there are 635 billion bridge hands.

[the hog]

Not saying you are a liar, but this problem is well known and not just in one book. Rather than question me, why don't you say when on BBO it was and against whom?

[1eyedjack]

Not saying you are a liar, but this problem is well known and not just in one book. Rather than question me, why don't you say when on BBO it was and against whom?

For the time being it is still up there:

 

http://online.bridgebase.com/myhands/hands...sername=ralph23

[the hog]

Thanks Jack. Interesting to see a book hand appear as a real hand.

[ralph23]

Thanks Jack. Interesting to see a book hand appear as a real hand.

Your turn now. What books, what pages? I'd love to see this particular set of two hands actually appear in print someplace.

 

Did you think I was stupid enough to lie about something so easily verified or falsified?

Edited September 5, 2007 by ralph23

[han]

Thanks guys.

[the hog]

Thanks Jack. Interesting to see a book hand appear as a real hand.

Your turn now. What books, what pages? I'd love to see this particular set of two hands actually appear in print someplace.

 

Did you think I was stupid enough to lie about something so easily verified or falsified?

Didn't say you lied Ralph, just said this is a book hand. I can't tell you which book(s) as I don't have my library with me in Laos. However I am sure others can point you in the direction. This hand, maybe different suits but same layout, is wll known as a teaching example as I have said.

[ralph23]

Thanks Jack. Interesting to see a book hand appear as a real hand.

Your turn now. What books, what pages? I'd love to see this particular set of two hands actually appear in print someplace.

 

Did you think I was stupid enough to lie about something so easily verified or falsified?

Didn't say you lied Ralph, just said this is a book hand. I can't tell you which book(s) as I don't have my library with me in Laos. However I am sure others can point you in the direction. This hand, maybe different suits but same layout, is wll known as a teaching example as I have said.

Oh. Right.

[hrothgar]

One comment:

 

It's entirely possible that you are both right.

 

1. The play example is well known. (I am quite sure that the layout of the club suit can be found in any number of books. If anyone really cares, I'll take a look at Watson over the weekend)

 

2. Ralph (obviously) played the hand on BBO.

 

The interesting question is whether this hand was "randomly" generated by the Great Shuffler. Alternatively, were you playing in a tournament where the Director might have chosen to use pre-generated hands.

 

There are a lot of examples where directors (real world and online) have chosen to "juice" the deals that they use in tournaments for any one of a number of reasons.

[Finch]

Umm... there's a reason why these hands come up in books, it's because they are good plays that people should be aware of.

 

I've seen quite a few 'textbook' hands at the table... the trick is to notice them when they come up.