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What are cover cards?

#1 User is offline   nick_s 

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Posted 2009-December-28, 16:13

Hi,

I often use the Losing Trick Count (LTC) to double check a proposed bid when in doubt. I make adjustments for Aces, Queens, and extra trumps - and try not to get too religious about it.

I've seen people mention cover cards in relation to the LTC, and I've no idea what this is nor how to use it :)

I'd be grateful if someone would explain this for me - or point me to a reference.

Thanks,
Nick
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#2 User is offline   kenrexford 

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Posted 2009-December-28, 16:35

Roughly, "cover cards" is a method of assessing losing trick count that is more precise, based on more precise info.

LTC is a rough cut. You take your loser count (say, 8 losers) and add then to partner's expected/announced LTC (say, 6 losers) and get a total loser count (in the example, 14), You subtract the total from 24 (24-14=10) to get the expected tricks.

But, back up. If partner has an expected 6 losers, you can also check your "cover cards." Suppose you have two Aces and a Queen. Presumably both Aces are cover cards. The Queen, however, is a cover card if in partner's length but not so much oppoiste partner's shortness.

Take an example. You have Axxx 10xx xx AQxx. By pure LTC, this is an 8-loser hand.

Give partner two different 6-loser hands:

KQJxx x Ax Jxxxx
KQJxx Jxxxx Ax x

Adding LTC+LTC, subtracted from 24, and both should make. But, 4 likely fails on the second. Why? Cover card analysis. The question was (primarily) whether the Queen was "working."

Now, what to count as "cover cards" is more difficult. Assessing honors seems easy, but it is not. A Qx is a cover card opposite AKx, but it is sometimes actually two cover cards, in a sense. The doubleton itself reduces the losers to 0 in the suit (if you can ruff out the third), but the Qx means that you might instead use the three-card combination to pitch something else. Thus, if you have, say, xx-xxx opposite partner's AKx-Axx in the minors, you expect to lose two minor cards, because of the ability to ruff the third diamond. Make your minors Qx-xxx, and now you can pitch the third club and end up with one loser only (ruffing the third club, instead). But honors are usually pure. (Notice how LTC does not help this situation at all.)

Shortness is a "cover card," but it depends. A stiff operates (with sufficient trumps) as two covers opposite Axx. But, it is not a single cover card opposite KQJ, the latter being one fewer losers for Opener and one fewer losers for Opener. Thus, shortness-based "cover cards" depend much on what partner precisely has. Hence, you want to be able to show partner "shortness covers" so that he can assess how much that "shortness cover" is really worth. (Try finding a method to describe Qx as a combo cover! Ain't gonna!)
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#3 User is offline   Siegmund 

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Posted 2009-December-28, 16:57

Oversimplifying greatly: Cover cards are at their best when one partner has already shown (or denied) shortness. Then the other partner counts only-top-tricks opposite the shortness, but any A K or Q opposite the long suits.

A useful approximation along the same lines - after an auction like 1-1-2, any A K or Q in diamonds or spades is a cover, but in the round sounds, I'd count an ace as 1, a king as 1/2, and a queen as nothing.

Even with that kind of a crude understanding, "loser minus covers" runs circles around "24 - (losers + losers)" for accuracy, and things like splinters and game tries become spectacularly more valuable to you than they are to a point-counter. (And in such a framework, there's a compelling reason not to show singleton aces and kings as "shortness" since you will cause your partner to mis-evaluate his kings and queens facing them.)
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#4 User is offline   Old York 

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Posted 2009-December-28, 17:50

A cover card is any high card that can be expected to eliminate a loser in partner's hand. If your partner's bidding suggests 7 losers, then you need 4 cover cards to raise to game.

After a trump fit has been agreed and you are balanced, or when partner has shown a balanced hand and you hold the long suit, counting cover cards can help place the final contract

If partner is known to be unbalanced, then LTC should be used because it as impossible to evaluate side suit cover cards... they may have no value, similarly if you hold a singleton then it may be impossible to evaluate partner's cover cards

A 16-18 point hand can be expected to supply 4-5 cover cards
A 13-15 point hand can be expected to supply 3-4 cover cards etc

So, if you hold the long suit simply deduct partner's cover cards from your losers

Tony
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#5 User is offline   nick_s 

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Posted 2009-December-28, 22:16

Thanks all. That was very helpful. I think I'm starting to get it now :lol:
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#6 User is offline   P_Marlowe 

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Posted 2009-December-29, 02:30

Hi,


it may have already been mentioned, but I did not find it explicit

"Cover Cards" is a concept, which you can apply if you hold a bal.
hand, and partner holds an unbal. hand, or if you hold a unbal.
hand and you are facing a bal. hand.

As a simple example take the infamous Axx Axxx Axx Axx

From a LTC perspective, this hand has 8 losser, but there exist an
adjustment, that you can upgrade, if holding all 4 Aces, i.e. the hand is
worth 7 looser.
But if you apply cover cards, you have 4 cover cards, and if you are
facing a 7 looser hand with a major suit fit, than you "know", that you
will have at most 3 combined loosers.
Using the above mentioned adjustment you still get to the same answer,
but you get the idea, cover cards are for bal. hands, LTC is for unbal.
hands.

Cover Cards can also be used, if you define your preempts in term of
loosers, than Cover Cards will help you to make more precise decisions.

With kind regards
Marlowe

PS: It was mentioned, that shortness is a "Cover Card", from the above
you should figure, that if you happen to hold shortness, you should use the
LTC, because you have an unbal. hand.
With kind regards
Uwe Gebhardt (P_Marlowe)
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