Verschillen

Dit geeft de verschillen weer tussen de geselecteerde revisie en de huidige revisie van de pagina.

--- bridge:systeem:verdediging-tegen-ekren [2020/12/19 16:10] – oude revisie hersteld (2007/09/24 14:44) 213.166.79.21
+++ bridge:systeem:verdediging-tegen-ekren [2021/03/13 00:03] (huidige) – Externe bewerking 127.0.0.1
@@ Regel 3: / Regel 3: @@
 Verdediging tegen 2♣/♦/♥ openingen die (mogelijk) een zwak spel met beide hoge kleuren aangeven.
+====Het voorstel====
+==Pas==
+Verschillende betekenissen:
+  * Niet genoeg om te bieden.
+  * "Trap pass", later wil je voor straf doubleren.
+  * Balanced 22-24, over een 2♥-opening 21-24 (dan is 2♥ bod waar de 21-22 SA in zit niet beschikbaar).
-====Het voorstel van Hans====
-  * Pas=verschillende betekenissen:
+==Doublet==
-    * Niet genoeg om te bieden.
+Verschillende betekenissen:
-    * "Trap pass", later wil je voor straf doubleren.
+  * Transfer naar de volgende kleur
-    * Balanced 22-24, over een 2♥-opening 21-24 (dan is 2♥ bod waar de 21-22 SA in zit niet beschikbaar).
+  * 19-20 SA. Over alle SA biedingen, zowel in eerste als in tweede instantie, die SA varianten aangeven spelen we Niemeijer.
-  * Doublet=verschillende betekenissen:
+  * SF in een kleur
-    * Transfer naar de volgende kleur
-    * 19-20 SA. Over alle SA biedingen, zowel in eerste als in tweede instantie, die SA varianten aangeven spelen we Niemeijer.
-    * SF in een kleur
-> Werkt het combineren van een transfer met de andere betekenissen? Min ervaring is dat dit alleen werkt bij grote verschillen in kracht tussen de standaard (zwakste) betekenis en de sterke varianten. Partner is gedwongen uit te gaan van de zwakste betekenis, in de geval de transfer. Als je tegenover dat volgbod meer wilt en gaat bieden, hoe hou je dan met een van de andere betekenissen de bieding onder controle? Lijkt me lastig.
+> Werkt het combineren van een transfer met de andere betekenissen? Partner is gedwongen uit te gaan van de zwakste betekenis, in de geval de transfer. Als je tegenover dat volgbod meer wilt en gaat bieden, hoe hou je dan met een van de andere betekenissen de bieding onder controle? Lijkt me lastig.
-  * 2♦=transfer naar harten, 12-16 punten.
+==2♦==
-  * 2♥ (indien beschikbaar) = Verschillende betekenissen:
+Transfer naar harten, 12-16 punten
-    * Transfer naar schoppen, 12-16 punten
+==2♥ (indien beschikbaar) ==
+Verschillende betekenissen:
+  * Transfer naar schoppen, 12-16 punten
   * 21-22 SA
-  *2♠ = Verschillende betekenissen.
-    * Unusual. Beide lage kleuren, 12-16 pnt.
-    * Mancheforcing met een eigen kleur.
-    * Mancheforcing balanced.
-> Dit vind ik handig. Doordat 2♠ unusual is (ipv 2SA), komt een eventueel SA-contract in de goede hand.
-> Best. Ik vind het eigenlijk niet nodig hier verschil te maken tussen semi- en mancheforcing. Geldende aanpak is dat je na een preempt van tegenstanders de eerste 5/6 punten van je maat zelf al meebiedt. Met die aanpak heb ik praktisch nooit ongelukken. Een semi-mancheforcing durf ik dus wel als mancheforcing te verlopen. Maar als je de ruimte toch hebt...
-  *2SA=16-18 balanced. Hierover Niemeijer.
+==2♠==
-  * 3♣/♦/♥/♠=natuurlijk volgbod, 17 of meer punten
+Verschillende betekenissen.
+  * Unusual. Beide lage kleuren, 12-16 pnt.
+  * Mancheforcing met een eigen kleur.
+  * Mancheforcing balanced.
-> Waarom zo veel? Het is m.i. prettig om vanaf 14 punten te kunnen "bieden wat je hebt"
+==2SA==
+-18 balanced. Hierover Niemeijer.
+==3♣/♦/♥/♠==
+Natuurlijk volgbod, 17 of meer punten
 ===In de vierde hand===
 In de vierde hand kunnen we na een 2♦ antwoord op de 2♣ opening nog spelen wat we spelen na een 2♦ opening. Na een 2♥/♠ antwoord kunnen we verdedigen alsof er Muiderberg geopend is door de rechtertegenstander.
-====Het voorstel van Pieter====
-Combineren van transfers op twee niveau, het 2♠-bod voor de lage kleuren met de balanced dubbel van de Noren
-  * pas=12-14 balanced (mogelijk)
-  * dbl=15+ balanced
-  * 2♦/♥=Transfers naar 2♥/♠. In principe 12-16, sterker kan (je komt nog eens aan de beurt)
-  * 2♠=unusual, 5/4 of beter in ♣/♦.
-  * 2SA=unbalanced, te sterk voor volgbod (18+)
-  * 3♣/♦=Natuurlijk, 13-17
-  * 3♥/♠=stopper met lange semi-dichte lage kleur (deze betekenis alleen als de transfer naar dezelfde kleur beschikbaar is)
-> We moeten het ook over de het bieden na (2x) - pas (3/4 ♥/♠) hebben.
-==== Norwegian defence ====
-Kan nooit kwaad om te kijken wat anderen verzonnen hebben. Dit kon ik nog uit een internet archief lospeuteren.
-=== Defending Ekrens 2 diamonds ===
-By Tor Eivind Høyland {Norwegian} - translated with permission from [[http://www.bin.no/|//Bridge i Norge//]]: Feb. 1997
-Ekren 2♦'s power is to show defined suits rapidly Used with discipline this is a formidable weapon. Its biggest strength is that frequently the final contract will be reached in one round - all before your opponents can communicate their values or distribution. This alone makes defending an Ekrens opening difficult. On the other hand there are the usual weaknesses of this sort of destructive opening      * Your opponents probably have the balance of honour strength    * Not infequently the auction becomes a high level guessing game My experience has been that Ekrens players often stretch a level too far. However they rarely get punished for such impudent bidding. As their opponents we do have some information: at least we don't have to look for playable spot in the majors! The chance of a successful major game against Ekrens is small. Our defence should be based on different lines.     * Is 3NT playable?    * Should we be in minor suit game?    * Can we make a minor slam? And always of course keeping our scythe sharp .. to gather in those doubled undertricks that Ekrens openers so frequently provide!
-== Method ==
-More than against any other weak two, a double of Ekrens should show a balanced 15+. It makes no difference whether this is from 2nd or 4th hand
-♦  double
-♦  pass  2♥/♠  double..
-both showing a strong no trump or better. Doubler's partner can now apply total trick theory to decide whether to leave in the double.
-♦  double  2♠  double
-Here the second double shows four or more spades and some values. Similarly in the delayed sequence
-♦  pass  2♠  double  \\     pass ?
-You should usually pass out the double with 4 spades. Although this seems risky you will get a lot of tops, and on balance your good scores will outweight the disasters.
-One warning: you must be disciplined about the strength of the initial double and never make it with a major singleton which will throw out partner's trump estimation.
-Furthermore with a 2245 shape you should be looking at minor aces and kings, rather than lesser honours.As I have recommended against the Multi, your 2NT overcall should
-show some type of unbalanced hand. Against Ekrens this should furthermore be minor orientated, bearing in mind that we are looking toward contracts in either no trumps or a minor.
-♦  2NT  \\2♦  pass  2♥/♠  2NT
-showing a good unbalanced minor orientated hand (at least 5/4)Advancer can now chose to play in 3♣/♦. Bids of 3♥/♠ indicate stops with a view to 3NT. Such bids can of
-course also be advance cues - on the way to minor suit slam.Direct overcalls of 3♣/♦ are strong one-suited hands. Should you also hold a 4 card major (say a 4153 shape)
-then assume this major is the enemy's suit. Thus strong hands of this type should still make a three level minor overcall. How about moderate hands? Say the bidding goes
-♦  pass  2♥  pass \\     pass  ?
-A delayed double shows 12-14 points with 2-3 hearts. Holding 4 hearts it is generally better to pass. Your partner won't have enough hearts to stand your double, and should
-his takeout flounder you will have preferred to simply taken some undoubled undertricks. 2NT again shows a minor orientated hand, but not good enough to bid on the first
-round. We still know that Ekrens opener has 4+ spades, and so at least won't be ending up in a spade contract!
-== A Digression ==
-♦  pass  2♥  2♠
-Shows good spades,  whereas
-♦  pass  2♠  3♥       ...
-shows an even better heart holding. You might find this inconsistent. Perhaps it is, but I have not been able to devise any useful conventional meanings for these bids.
-If you have better ideas - please write in!
-{Presumably direct 2♥/♠ overcall by 2nd hand also shows a strong one-suited hand - the article doesn't say. Ed}
-Now these are the easy auctions. There is a a good probability that we shall get our plus score, as the opponent's bidding suggests they don't have a safe contract. However it does not always go so easily, and you may have some difficult decisions to make
-♦  pass  3♥/4♥  ?
-A double still shows a 15+ balanced hand type. We can't let them steal our hand! However partner will have a difficult choice and must count the trumps carefully. If they jump to 3♥/4♥ you should bear in mind who your opponents are, and the state of your match before taking action. Remember that the Ekrens opening has a wide range. If responder were genuinely strong he would commonly have enquired with 2NT to clarify this.An overcall of 3NT (or 4NT) still shows a minor orientated hand, generally unbalanced. You are under considerable pressure, but must not give up (at least at pairs).
-♦  double  3♠  ?
-More problems. Opponents seem to have good fit, but 3NT might still be on. However if opponents have fit then so have we! Double is best played as a spade stop, interested in the no trump game. Partner will have to decide whether to bid 3NT or take the money.3NT here is better played as both minors and game values but denying anything in spades. A direct 4♣/♦ should be a good suit. Pass is well .. pass and partner should give up without extra values. If he bids 3NT it is to play, whereas another double is takeout. Bear in mind that he didn't bid no trumps initially, and so won't hold the only minors.
-♦  double  4♠  ?
-Now we are in deep trouble. You just have to do what you can and remember the principles. For the foolhardy ..
-♦  pass  3♠  pass\\     pass   ?
-NT here shows a minor two-suiter not good enough for initial overcall. Double is 12-14 with at least one spade stop. Remember opponents will have 8-9 card fit, on assumption that they are bidding up according to total trick theory. On the same basis the LAW predicts that we will not get an adequate score by doubling them. The "spade stop" agreement leaves chances of a successful 3NT contract (honours in opponents suits being a so called "trick reducing factor"). But this sort of thing is too risky for me. If opponents can take 2 spade tricks straight off it is unlikely that either no trump or minor game will succeed and it seems best to pass.
-== Examples - Santiago Championship and other events ==
-I have tried to use play at Santiago to test out these principles. Examples are of course quite random and limited, for often no action was appropriate. I have added in some of Bjørn Olav's own deals from our previous discussion {Bridge i Norge 2-94} to explore our method against his. There were no records of the Santiago Round Robin, but this deal came up in the 8 team final stage:
-| Teams\\ both vul\\ dealer\\ West | North hand\\  ♠ A4 \\ ♥ A7642 \\ ♦ Q53 \\ ♣ AKJ |  |
-| West hand\\  ♠ K765 \\ ♥ Q983 \\ ♦ A82 \\ ♣ 53 |   | East hand\\  ♠ Q82 \\ ♥ J \\ ♦ KJ7 \\ ♣ Q98642 |
-|  | South hand\\  ♠ J1093 \\ ♥ K105 \\ ♦ 10964 \\ ♣ 107 |  |
-Most N/S pairs bid to a heart contract, but had Geir and Tor sat E/W and opened 2♦ the bidding using our defence should have gone
-^ West ^ North ^ East ^ South ^ notes ^
-| 2♦ | double | 2♠ | double | 2♦=Ekren both majors |
-| pass | pass | pass |  |  |
-With 2♠ doubled going two off this is a a fine result. Note that on traditional methods North will bid 2NT - down 1-2 tricks in practice.
-Now the quarter-finals ..
-| Teams\\ both vul\\ Dealer\\ North | NORTH hand\\  ♠ K987 \\ ♥ AJ102 \\ ♦ 9643 \\ ♣ J |  |
-| WEST hand\\  ♠ J \\ ♥ K965 \\ ♦ AJ7 \\ ♣ AK1096 |   | EAST hand\\  ♠ A1062 \\ ♥ Q7 \\ ♦ K102 \\ ♣ Q752 |
-|  | SOUTH hand\\  ♠ Q543 \\ ♥ 843 \\ ♦ Q85 \\ ♣ 843  |  |
-The usual contract was 3NT making 10, but say we were defending against North's Ekrens. (and playing in "sparkling" form) ..
-^ West ^ North ^ East ^ South ^ notes ^
-|     |  2♦  | pass |  2♠  | 2♦=Ekren both majors |
-| 3♣  | pass |  3♠  | pass |   |
-| 4♣  | pass |  4♦  | pass | |
-| 4NT | pass |  5♦  | pass |  |
-| 6♣  | pass | pass | pass |  |
-Are you an imaginative slam bidder? I hope you are going to find that queen of diamonds. Note that we have to bid 3♣ directly. We don't care about hearts - that's their suit.
-A further inference is that East's cue bid has to be the ♠A opposite his partner's likely singleton. With doubleton spade West would have doubled!
-Returning to reality, here is deal 93 from the semifinal against Brazil.
-| Teams\\ both vul\\ Dealer\\ North | NORTH hand\\  ♠ J983 \\ ♥ void \\ ♦ J9842 \\ ♣ 10742 |  |
-| WEST hand\\  ♠ Q10 \\ ♥ Q852 \\ ♦ K1065 \\ ♣ A98 |   | EAST hand\\  ♠ K652 \\ ♥ 9763 \\ ♦ 3 \\ ♣ KJ65 |
-|  | SOUTH hand\\  ♠ A74 \\ ♥ AKJ104 \\ ♦ AQ7 \\ ♣ Q3 |  |
-At the table North passed - and so did Tor! South opened 1♥ and played there. But doesn't Tor have an Ekrens opening? Or isn't his 4414 seven count enough? Let's move on.On a more usual 2♦ opening would the Brazilians manage to extract a penalty? Probably not with North holding only 2 points and void hearts. Otherwise the deal would be a killing ground for Tor and Geir. Let's see if we can manage the business double:
-^ West ^ North ^ East ^ South ^ notes ^
-|   | pass | 2♦ | double | |
-| 2♥ | 2NT | pass | 3♣ | 2NT thought to be lebensohl |
-| pass | 3♦/3NT | pass | pass |
-| pass | ||| |
-North is looking at a heart void with a feeling that opponents have found their play level. With such a poor hand my recommendation (unfortunately) is to bid your own suit .. and our big plus score disappears. One comfort is that you can blame the methods in this article! |
-The first really interesting Ekrens came in the final
-| Teams\\ N/S vul\\ Dealer\\ West | NORTH hand\\  ♠ AQ3 \\ ♥ A8532 \\ ♦ 1095 \\ ♣ 76 |  |
-| WEST hand\\  ♠ J1096 \\ ♥ J1074 \\ ♦ A32 \\ ♣ 105 |   | EAST hand\\  ♠ 87542 \\ ♥ 96 \\ ♦ Q76 \\ ♣ KQ9 |
-|  | SOUTH hand\\  ♠ K \\ ♥ KQ \\ ♦ KJ84 \\ ♣ AJ8432 |  |
-^ West ^ North ^ East ^ South ^ notes ^
-| 2♦ | pass | 3♠ | 3NT | 3NT = minor oriented |
-| pass | pass* | pass  |  | *=holding the majors |
-Unfortunately at the table Leufhen's 3NT **didn't** show the minors and they bid to 4NT - with 3NT cold. On a spade lead you make 3NT by leading out king of diamonds, taking 6 major tricks and just 3 in the minors. The Dutch would have saved 12 IMPs had they played our defence.
-Ekrens was back again on deal 107
-| Teams\\ both vul\\ dealer\\ South | NORTH hand\\  ♠ J \\ ♥ Q98 \\ ♦ J7654 \\ ♣ KQ84 |  |
-| WEST hand\\  ♠ AKQ5 \\ ♥ J64 \\ ♦ K983 \\ ♣ 105 |   | EAST hand\\  ♠ 962 \\ ♥ A72 \\ ♦ AQ \\ ♣ 97632 |
-|  | SOUTH hand\\  ♠ 108743 \\ ♥ K1053 \\ ♦ 102 \\ ♣ AJ |   |
-^ West ^ North ^ East ^ South ^ notes ^
-|         ||| 2♦ |  |
-| pass | 2♥ | pass | pass |  |
-| double | pass | 3♣ | pass | |
-| pass | pass ||  |
-The double shows 12-14 and 2-3 cards in hearts (recall you pass with four). East can now bid 3♣ and West passes without a fit. 2NT from East here would have been a 'scramble' - offering the choice of suit back to partner.At the table West was unable limit his hand in his way and his natural 2NT bid was left in .. more IMP's lost.
-Two examples from "Bridge Nytt"
-| Teams\\ nv/nv\\ dealer\\ West | NORTH hand\\  ♠ AQ \\ ♥ A943 \\ ♦ 42 \\ ♣ KJ632 |  |
-| WEST hand\\  ♠ J854 \\ ♥ KJ752 \\ ♦ 85 \\ ♣ A7 |   | EAST hand\\  ♠ K9632 \\ ♥ Q \\ ♦ 10976 \\ ♣ 1094 |
-|  | SOUTH hand\\  ♠ 107 \\ ♥ 1085 \\ ♦ AKQJ3 \\ ♣ Q85 |  |
-Bjørn Olav said that North had missed the boat in thinking he could bid on the next round. But you cannot assume that against Ekrens. The ideal sequence is
-^ West ^ North ^ East ^ South ^ notes ^
-| 2♦ | double | 4♠ | double | |
-| pass | pass | pass |  |  |
-Although North has only 14 points there are extras in the spade honour sequence, and a source of tricks in clubs should the bidding lead to to 3NT.
-♣ would be a fair alternative call. Once partner has doubled South can estimate that opponents are above their playing level with a maximum 9 trumps.
-A double is therefore appropriate even with his fine diamond suit.
-Another Bridge Nytt example
-| Teams\\ N/S vul\\ dealer\\ West | NORTH hand\\  ♠ void \\ ♥ Kxx \\ ♦ 10xxxxx \\ ♣ Qxxx |  |
-| WEST hand\\  ♠ KJxxx \\ ♥ Qxxx \\ ♦ Q \\ ♣ 10xx |   | EAST hand\\  ♠ Q10xxx \\ ♥ J10xx \\ ♦ x \\ ♣ Jxx  |
-|  | SOUTH hand\\  ♠ Axx \\ ♥ Ax \\ ♦ AKJxx \\ ♣ AKx  |  |
-Against Helgemo and Ekren in Ålesund, South was cautious, bidding only 3NT after 2♦ - 3♠. Let's look at what might have happened if North is as adventurous as Ekren himself!
-^ West ^ North ^ East ^ South ^ notes ^
-| 2♦ | pass | 3♠ | double |  |
-| pass | 4♦ | pass | 4NT |  |
-| pass | 5♣ | pass | 5NT |  |
-| pass | 6♦ | pass | 7♦ |   |
-Once partner shows 5-6 diamonds and values South is unstoppable. There are now many routes to the grand slam. How would another theoretician
-(eg Jan Mikkelsen) have bid? With Jan as South the bidding may have gone:
-^ West ^ North ^ East ^ South ^ notes ^
-| 2♦ | pass | 3♠ | double |  |
-| pass | 3NT | pass | 4♣ | 3NT=lebensohl - puppets 4♣  |
-| pass | 4♦ | pass | 4♥* | 4♥*=cue  |
-| pass | 4♠* | pass | 5♣* * | 4♠*=cue 5♣* *=can count 12 tricks in diamonds  |
-| pass | 5♥ | pass | 7♦ | 5♥=grand slam try  |
-Perhaps odd that 3NT should be Lebensohl, but this will rarely be the right contract once opponents know what to lead. If we have the values for 3NT
-a second double (as above) is the best call - offering partner choice between play and defence. So 3NT as lebensohl is appropriate. With a
-good minor 2-suiter you would jump to 4NT.
-{I personally find south's 4♣ opposite possible long clubs an incredible underbid on this hand. ParadoX solve this of course. And 5♥ surely another cue (clearly sniffing at the grand) Chris)
-To finish ..
-I have laid out some tools to find our own contracts, while keeping open possibilities of penalty doubles. I'll finish with an example from
-"Kretserien" playing these methods with Werner Lyseng. The deal:
-| Teams\\ both vul\\ dealer\\ East | NORTH hand\\  ♠ AKQJ9x \\ ♥ A10x \\ ♦ xx \\ ♣ Jx |  |
-| WEST hand\\  ♠ xx \\ ♥ 9xxx \\ ♦ Qx \\ ♣ Qxxxx |  | EAST hand\\  ♠ 8xxx \\ ♥ Qxxx \\ ♦ J8xx \\ ♣ A |
-|  | SOUTH hand\\  ♠ x \\ ♥ KJ \\ ♦ AKxxx \\ ♣ K10xxx |  |
-^ West ^ North ^ East ^ South ^ notes ^
-|             || 2♦ | pass |          |
-| 2♥ | double | pass | 4♦ |   |
-| pass | 4NT | pass | 6♣ | 4NT=to play |
-| pass | 6♠ | pass | 6NT |  |
-| pass | pass | pass |  |  |
-I was cowardly in passing on the first round as South. Had I bid 2NT **I** would have been declarer,
-and 6NT easily home on a club or heart lead. (How can East not play the ♥Q?). It isn't so easy played by
-North with ♥J holding the first trick. Werner might have crossed to ♠A and led a club to the king. After
-cashing the heart honours he then can squeeze East in the red suits. But to play like this you have to be a
-genius.My Aunt Agatha would probably have cashed the hearts and then run the spades. East has to keep three
-diamonds and ♣A leaving no room for hearts. Auntie wriggles home by playing a club to the king, and to her
-astonishment gets put back into dummy with a diamond! She's just happy have found the ace onside!Both these
-lines require four diamonds with the Ekrens opener, which isn't likely. Assume rather that he has the values
-for his opening and play him for short clubs including the ace. If West holds the ♣Q a really cunning line is
-a pseudo-finesse toward ♣J at trick two! Once this brings the ♣A the hand plays itself. This article was recommended
-to me by Bjørn Olav Ekren and is one of a series on defense in the Norwegian journal
-[[http://www.bin.no/|//Bridge i Norge//]] (February 1997).
-Reproduced here by kind permission of its editor Boye Brogeland. Special thanks to Liverpool University visitors
-Maria Andersen and Mona Brun for their invaluable help in baseline translation from the original Norwegian.