[kgr]

If you have agreed to play obvious switch. A small card promises A or K in the obvious switch color and a high card denies it.
Is this agreement always valid or do you have exceptions when OS does not apply by agreement?

F.i.: Partner leads A and dummy has Qxx(x):
Is OS agreement still valid and partner has to lie about OS color if he wants/does not want a switch. Or did you specifically agree that OS is not valid and a small card simply encourages in the suit itself?

[akhare]

 kgr, on 2013-August-10, 03:03, said:

If you have agreed to play obvious switch. A small card promises A or K in the obvious switch color and a high card denies it.
Is this agreement always valid or do you have exceptions when OS does not apply by agreement?

F.i.: Partner leads A and dummy has Qxx(x):
Is OS agreement still valid and partner has to lie about OS color if he wants/does not want a switch. Or did you specifically agree that OS is not valid and a small card simply encourages in the suit itself?

Good questions -- after playing OS for a while, we recently switched away from it (pun fully intended .

A few comments:

1) We used to play against suits, A and Q asked for attitude about the led suit and that only the K was for OS. Note that at the 5+ level, we stipulated that the K was always count and that leading the A denied the K.

2) If the K was led against a suit contract in which the count was completely unknown and dummy came down with Qxx(x), we would give count. IMO, in such situations, standard count tends to be less ambiguous, but YMMV.

3) OS works great in the positive case (switch to OS), but on the flip side, opening leader sometimes can't tell whether third hand really wants the suit to be continued. I don't recollect it as being a significant problem, but it's something to keep in mind

4) If dummy came down with a stiff (or it was clearly wrong to continue the suit), our agreement was to signal OS. Since the standard agreement is to give SP when dummy is short. One can argue that standard signals might be able to give a three way signal (upper, lower, neutral), but it really depends on the spot card and is therefore likely to be a wash.

[kgr]

Thank you for the answer

 akhare, on 2013-August-10, 21:10, said:

Good questions -- after playing OS for a while, we recently switched away from it (pun fully intended .

We are generally happy about it and don't plan stop playing it. Did you stop it because it was giving more disadvantages than advantages?

 akhare, on 2013-August-10, 21:10, said:

1) We used to play against suits, A and Q asked for attitude about the led suit and that only the K was for OS. Note that at the 5+ level, we stipulated that the K was always count and that leading the A denied the K.

We play OS and in the next trick(s) suit preference. Because we don't give count, we lead count from sequence: highest from even, second from odd (HESO). Therefore we cannot make the distinction in the lead to ask a different thing.

 akhare, on 2013-August-10, 21:10, said:

2) If the K was led against a suit contract in which the count was completely unknown and dummy came down with Qxx(x), we would give count. IMO, in such situations, standard count tends to be less ambiguous, but YMMV.

Because we lead HESO (see above) responder often knows if it is ok to continue the suit or not.
=> If we still play OS by agreement then responder can lie about it if he thinks it is better, but maybe it is better not to play OS by agreement in this case: this avoids confusion for the opening leader concerning the OS-suit.

 akhare, on 2013-August-10, 21:10, said:

3) OS works great in the positive case (switch to OS), but on the flip side, opening leader sometimes can't tell whether third hand really wants the suit to be continued. I don't recollect it as being a significant problem, but it's something to keep in mind

certainly true. You could even think that this disadvantage compensate for the advantage. The number of times that opening leader needs to know about OS is the same as he needs to know about opening suit.
...but our feeling is that this is not true, we still think that OS suit is more important. (e.g: if lead was from AKQ, if dummy is short in lead suit,..)

 akhare, on 2013-August-10, 21:10, said:

4) If dummy came down with a stiff (or it was clearly wrong to continue the suit), our agreement was to signal OS. Since the standard agreement is to give SP when dummy is short. One can argue that standard signals might be able to give a three way signal (upper, lower, neutral), but it really depends on the spot card and is therefore likely to be a wash.

We also still play OS in this case.
...that is making the agreement easier: always OS.
....and therefor I'm reluctant to not play OS by agreement when dummy has Qxx(x).

[mike777]

 kgr, on 2013-August-10, 03:03, said:

If you have agreed to play obvious switch. A small card promises A or K in the obvious switch color and a high card denies it.
Is this agreement always valid or do you have exceptions when OS does not apply by agreement?

F.i.: Partner leads A and dummy has Qxx(x):
Is OS agreement still valid and partner has to lie about OS color if he wants/does not want a switch. Or did you specifically agree that OS is not valid and a small card simply encourages in the suit itself?

Not sure what your question is but OS is much more than this. If you play OS then yes OS and all its rules apply. The book is several hundred pages long. Keep in mind to fully answer a question we need to know the bidding, contract, rest of dummy and our hand.

If you are only going to play one or two OS rules out of many then I would not claim you play OS.

http://www.bridgetod...witch/index.php

http://www.bridgewit...viousShift.html

[straube]

I'm akhare's partner so we shared the same adventure playing OS. At first I thought OS was a bit magical because sometimes we found an otherwise dangerous switch (leading away from a high honor for example) that was important for defending the hand. Eventually though we started to find more and more exceptions for OS. I think that the authors themselves recommend count signals when Qxx is in dummy so that's one. Let's say partner leads the A from AK and I have a small doubleton...I just want a ruff and don't want to signal OS. Frequently I had a high honor in the switch suit and had to signal I had it so partner would know how to defend the hand. Now frequently he would not switch because switching wasn't right, but then I asked myself how useful that information really was to him compared to attitude about the suit he was leading. Now we're playing attitude toward the suit lead, followed by count in the suit if partner continues it. If attitude doesn't make sense trick one, then it's count. If count doesn't make sense, it's suit preference. I think this is what most of the world is doing. We've recently been reading David Bird's book on defensive signaling and I would recommend it.