[mike777]

Watching Canvendish Vugraph saw this comment:

"The major difference on defense between experts and non-experts is that experts signal frequent suit preference." Larry Cohen

[luke warm]

this is, by my count, 3 or 4 times mike has tried to steer the conversation toward suit pref defense ... since he converted me to obvious shift, so i'll just come out and ask - are the granovetters the only ones who think os is superior to attitude/count/whatever?

[mikestar]

I think OS is an excellent method for an established partnership. I think that many are reluctant to teach it to inexperienced players.

SP is less often falsecarded but this doesn't always help declarer--he often knows what suit you should shift to even before he sees the signal. I think that SP gives declarer more reliable information than other signals, but less new information.

Also, SP can be falsecarded sometimes--any signal can be faked with impunity when you are certain that partner can never get the lead or that his lead is irrelevant (his entry is the setting trick, for example).

[sceptic]

I hope some one comes to BIL to teach us Obvious Shift, I would love to see what it is just to understand it.

[helene_t]

I'm surprised since here in the Netherlands a lot of intermediate players play "Roman Lavinthal", which means that an even card is allways SP. To some even the lead of an even card asks a shift! I don't have the expertise to judge the merrits of such agreements but at seems that in this way intermediate players make more SP signals than experts do. Of course there are experts that play Roman Lavinthal in certain contexts, typically at trick one.

[whereagles]

Well, some people around here play odd/even carding ALL the time. A method that is technically unsustainable since very often you can't understand whether pard encouraged with even or which suit he signaled. Odd/even should be a discard thing only, or when the person using it already showed 5+ cards in the suit (so that his signal can be clearly understood).

Playing "lead of an even card = asks for a switch" suffers from the same problem: it cannot be followed mechanically by pard, and it's often difficult for him to evaluate the situation.

As for frequent suit preference, well, not only do you need an expert pard that can watch the cards, but also he'll have to be VERY concentrated. As for obvious shift, I've played that for a year or two and was happy with the result.

[Chamaco]

whereagles, on May 11 2005, 08:32 AM, said:

Well, some people around here play odd/even carding ALL the time. A method that is technically unsustainable since very often you can't understand whether pard encouraged with even or which suit he signaled. Odd/even should be a discard thing only, or when the person using it already showed 5+ cards in the suit (so that his signal can be clearly understood).

This sounds a bit exaggerated :-)

Many players play Roman carding all the way, of course there are weird situations, but the same hapens with std or udca when uoi have only low or high cards and you miss the right card to signal.

In Roman carding, an even card is a mild suit preference, but pard should try to work out the hand to verify whether it makes sense or not.

When you hold only odd or only even cards, some players play that high encourages, others play that low encourages, or others play some other subtleties.

The idea that odd-even should only be used for discards sounds a bit.... ODD to me !

[whereagles]

Well, while it MAY be possible to read pard's odd/even signal accurately most of the time, it's is VERY stressing having to do that. I played a major championship like that and it was a horrible experience. I much rather concentrate efforts on something else than trying to decypher what cards pard may have had and why did he signaled like that.

Standard or UDCA gets the job done in the vast majority of the cases and it's not stressing at all. In the case of UDCA I actually find it very easy to read pard's card, even if declarer is up to some funny falsecard. (Not so easy in standard if declarer is tricky, though.)

[Chamaco]

whereagles, on May 11 2005, 10:52 AM, said:

Well, while it MAY be possible to read pard's odd/even signal accurately most of the time, it's is VERY stressing having to do that. I played a major championship like that and it was a horrible experience.

When you are used to a specific carding and you switch to another for a single tournament, it usually generates stress, because one is not used to play it regularly.

A much more fair test would be: play Roman carding for a full year until both you and your pard get used to it, and then compare it to UDCA or standard :-)

My guess is you'll find out that the pros/cons even out.

[whereagles]

I didn't only play odd/even that tournament. I played it also for 6 months with my current live pard. After a series of defense misunderstandings due to difficulties in interpreting the cards played, I realized odd/even was best used sparingly. Pard agreed and we now use odd/even only in clear-cut cases.

My current favorite is UDCA with odd/even on first discard or in known 5+ card suit.

[hrothgar]

Lets assume that we are interested in comparing the efficiency of three different discard structures across the set of cards (2:9)

System A: We will use high cards to encourgae and low cards to discourage. The cards 2-5 are "low" and 6-9 are "high"

System B: We will use even cards to encourage and odd cards to discourage. 2,4,6,8 are "even" and 3,5,7,9 are "odd".

System C: We will use prime numbers to encourage and complex numbers to discourage. 2,3,5,and 7 are "prime" and 4,6,8,9 are "complex"

In each case we have 4 different cards that we can use to encourage and 4 that we can use to discourage... You know what? It doesn't matter a damn which one of these structures you want to play... Sometimes you'll have the right card handy. Sometimes you won't.

If you want to have a meaningful discussion about defensive carding, I suggest focusing on the saliant issues.

Case in point: "Roman Discards" encode multiple pieces of information in the discard: If the discard is discouraging, it also provides suit preference information. Alternatively, the Granovetter's obvious shift principle uses the information channel to encode different information than traditional discard strucutres.

In short, define the information set that you need to describe THEN worry about implementation.

[helene_t]

hrothgar, on May 11 2005, 02:13 PM, said:

It doesn't matter a damn which one of these structures you want to play...  Sometimes you'll have the right card handy.  Sometimes you won't.

Yes and no. It is certainly more important what information you signal (only attitude, only SP, a combination of both, a "neutral" option etc.) than how you encode it. But if you play high/low you will often have the dillema that the most obvious "high" card is also too expensive to use as a signal. With odd/even you are slightly less likely to have that problem. Then again, when partner discards the six you may have to consider that it could be the most odd card he could afford since the only really odd card he had was the nine. I'm not sure if the notion that six is more odd than four is clear to all users of o/e signals. The ranking should be 35798642 (or is it 97532468? Someone correct me if I'm wrong), if you compare the high-low ranking to the o/e dichotmy then clearly high/low is more efficient.

This is all academic, at least as far as I'm conserned. I would say that for practical purposes Whereagles is right.

[kgr]

sceptic, on May 11 2005, 05:38 AM, said:

I hope some one comes to BIL to teach us Obvious Shift, I would love to see what it is just to understand it.

... I will have to change my level from advanced to Intermediate

Can somebody give definition (or short explanation) of Obvious Shift and Suit Preference. And an example to clarify will probably help.

Thanks

[Chamaco]

helene_t, on May 11 2005, 12:27 PM, said:

This is all academic, at least as far as I'm conserned. I would say that for practical purposes Whereagles is right.

I think the point is simply that o/e allow more complicated signaling method, encoding suit pref.

Sometimes it becomes too complicated or inappropriate (suit pref is not what you want, OR it is harder to decode).

Some other times, the extra info you get allow you some plus.

My guess is that this evens out in the long run.

[whereagles]

It might even out technically, but in terms of stress caused, I don't think it will ever compensate.

[inquiry]

I want to add something on O/E discards.

I think many partnerships more often run into an ethical problem with odd/even discards. Playing udca or standard, you generally play your highest or lowest card (when highest you may have to reflect if you can afford the high card... .I have run into cases where I had to keep a seven to guard against the six in dummy to prevent partner from being squeezed). This is easy enough, and is generally played without thought.

New comers to odd/even however, run into cases where either they don't have the required odd or even card. Then they spend some time (at the table), pulling first one card or then another. Finaly they play a card and their partner without effort is able to figure out they lacked the right kind of card. Or they will have only a small even card when they want a high one. Then they anquish over this as well... but if they wanted to play a small even on it hits the table at the speed of light.

This is NOT to say that all o/e players do this (in fact I have played o/e), or that most do it. It just that some do it. And this is not to say that they do it on purpose or that their partners realize that they are taking advantage of the speed of play of the card ("I worked it out on my own that my partner card couldn't mean what it looked like it meant, how dare you suggest otherwise.).

This is not meant to condemn o/e carding. I happen to like it. This is just a reminder to those who practice this carding method to train themselves to play their cards in tempo. Not with blazing speed when they have "just the right card" and with noticable break in tempo when they do not. But of course, we should all train ourselves to play at an even tempo. And yes, people playing standard carding often have tempo problems too... this is not limited to carding system, it just seems to occur more frequently in my experience with O/E carding... maybe ohters have different views.

Ben

[kgr]

Quote

And yes, people playing standard carding often have tempo problems too... this is not limited to carding system, it just seems to occur more frequently in my experience with O/E carding... maybe ohters have different views.

I don't see any reason why O/E discards would give more discard issues then standard discards.
Discarding on ♥: I can ask ♦ with a low even ♣, a high even ♠ or an odd ♦. I don't think this gives more issues as standard discards.

[mike777]

kgr, on May 11 2005, 07:46 AM, said:

sceptic, on May 11 2005, 05:38 AM, said:

I hope some one comes to BIL to teach us Obvious Shift, I would love to see what it is just to understand it.

... I will have to change my level from advanced to Intermediate

Can somebody give definition (or short explanation) of Obvious Shift and Suit Preference. And an example to clarify will probably help.

Thanks

Here is very short summary of "Obvious Shift" "OS"

Rule one: Count the hands, visualize the hands, look at dummy, review the bidding, try and remember p opening lead card, use whatever your level of common bridge sense and experience is. If a newish player try and visualize declarer hands using some common sense based on bidding and guess the shape of declarer's hand, any guess is better than none. Ok, now you are ahead of 90% of bbo defenders at this point.

rule two: If you know what the defense should be at this point, ignore p signals.

rule three: Using rule one and two should solve 90% of your defensive issues, "OS" can help solve some of the remaining issues. In general, at trick one you show attitude, trick 2 and etc you show suit pref, giving count is rare.

Rule four: You can never ask for a trump shift, p needs to figure that out on their own.


If you wish you can add odd/even at first discard only. Please note often by the time you make first discard partner has a wealth of information about your hand in this treatment.

Attitude=continue suit or shift partner, 200 pages of examples of what suit p should shift too. In general shift to our strong suits or opp weak suit. What is the "obvious shift" suit seems obvious to most of us but in fact experts can and do strongly disagree on what it is. In fact experts strongly disagree on when attitude or count or suit pref is on. This treatment codifies agreement on these issues.

Suit Pref=low card means lower suit, etc. Often you get to play suit pref when following in trump suit, low means like lower suits, etc. Keep in mind most of your carding at trick 2 and going foward are suit pref cards.

Count=rare, most common is in hold up situation or some rare slam hands when p needs count in a suit.

O/E on first discard only=odd means like suit, even means dislike and tends toward suit pref, low card =lower suit.

[cherdano]

hrothgar, on May 11 2005, 01:13 PM, said:

Lets assume that we are interested in comparing the efficiency of three different discard structures across the set of cards (2:9)

System A: We will use high cards to encourgae and low cards to discourage. The cards 2-5 are "low" and 6-9 are "high"

System B: We will use even cards to encourage and odd cards to discourage. 2,4,6,8 are "even" and 3,5,7,9 are "odd".

System C: We will use prime numbers to encourage and complex numbers to discourage. 2,3,5,and 7 are "prime" and 4,6,8,9 are "complex"

In each case we have 4 different cards that we can use to encourage and 4 that we can use to discourage... You know what? It doesn't matter a damn which one of these structures you want to play... Sometimes you'll have the right card handy. Sometimes you won't.

Hey Richard, that's evidently not true. 3,5,7,9 are all equally odd, and if you have only them, there is no information in the discard. OTOH, standard carding is not the same as your system A. If you have 5432, then you of course play the 5 to encourage. Partner seeing 96 in his hand and 8 in dummy will understand your 5 as high.

(Yes I know some agree that playing o/e, you play the highest from only odd cards to try to cancel the encouraging meaning.)

Arend