Friday, 8 June 2007

Doubles Webpage

I've created a new page to explain why I believe the EBU rules need to be changed.

Alerting of Doubles

Hopefully this means I'll be able to avoid cluttering up this blog with further rants on the subject. :)

Friday, 1 June 2007

Invitational Jump-Shifts

This method is quite popular amongst players of 2/1 GF: after a major-suit opening, a jump to 3 of a lower suit is invitational and shows a good suit (6+ cards). Personally I think this is a truly dreadful idea.

The problems aren't too difficult to spot. It's a very space-consuming response. This means that it will make subsequent bidding difficult, and you can't afford to make the bid on too wide a variety of hands.

In my experience the invitational jump-shift is almost guaranteed to put opener in a difficult position. Let's try these very ordinary hands, after the bidding starts 1S : 3D -

S AJ974
H J3
D Q5

Here perhaps partner can stop the hearts and you can run lots of tricks in NT. Or perhaps he can't. How are you going to find out, with no bid available below 3NT?

D 3
C 84

Here if partner has heart support you might belong in 4H, but alternatively the hand could be a complete misfit not making anything higher than 3D. Make the hand a little stronger and you know you should be in game, but will you find 4H if that's the best spot? How will partner know you have five hearts?

S AK965
H A53
D K842

A lovely hand in support of diamonds, but how do you distinguish this hand from all the other different shapes that might want to raise?

Of course, if you play a 2/1 as absolutely forcing to game, you do need somewhere to put these invitational hands. But not all invitational hands with a good suit are suitable for an IJS. It is dangerous to make an IJS on hands with tolerance for parnter's major, or with four cards in the other major, because of the possibility of missing a major-suit game. So playing IJS does not really solve the problem of what to do on these hands.

Much better, at least when one of these invitational hands comes up, is to be playing a system where a 2/1 is not absolutely forcing to game, with responder's rebid of his suit showing the invitational type. Starting at the lower level gives you so much more flexibility: not only does opener have an extra chance to describe his hand, but responder can make the bid on hands which are not such pure single-suiters, because he is not committed to showing the IJS type. For example, over 1S, hands with four hearts and a six-card minor are no longer a problem, because after a 2/1 response, responder can afford to raise a heart bid to game, and will only rebid his minor to show an IJS hand if opener does not have hearts.

Naturally this would make life more difficult when you do actually have a game-forcing single-suiter. But personally I think it is relatively easy to find a way to bid these hands. Even if constrained to play natural methods, I would much prefer to be playing 2/1 "GF except rebid" than absolute game-force. And with a bit of artificiality there is plenty of room in most cases to distinguish invitational from game-forcing hands without having to invent suits or NT bids. Certainly in a natural GF system, responder's 2-level rebids (when available) tend to be underused, and can be redefined to include the game-forcing single-suited type. Really I think that using a cheap response like 2C solely for natural game-forcing hands is a serious waste of space.

An alternative for people who want to keep their 2/1s as game-forcing is putting the invitational single-suiters into the 1NT response. This has several drawbacks. You don't get to show either the suit or the strength immediately, and if you later bid your long suit it might be difficult to distinguish this from a weaker hand. Also if 1NT is not forcing, you may well be missing a better contract if opener passes. It works better over a 1H opening than over 1S - particularly if playing Kaplan Inversion so that the "forcing NT" hand bids 1S rather than 1NT - because responder has a 2S rebid available as artificial to distinguish weak single-suiters from invitational ones. Even then, I still prefer making a two-over-one response, showing the suit immediately, if the system can be arranged to allow for it.

What does "Natural" mean?

Most bridge players understand roughly what to expect from a "natural" bid, but it's quite a difficult term to define precisely. This is unfortunate because, as well as being a useful word for describing what a bid means, it's also often used in system regulations and alerting regulations, where you really need a good definition.

The meaning also varies slightly depending on where you live. Let's look just at suit bids. In America, most people seem to consider a suit bid to be natural if it promises length in that suit, even if there is some additional information given. For example, a Muiderberg 2S opening (showing 5 spades and 4+ cards in a minor) would be described as natural. They would say it is "natural but conventional". The WBF, on the other hand, defines "natural" to be the opposite of "conventional". Of course, "conventional" is another term which is extremely difficult to define, but it is clear that the Muiderberg 2S is conventional, and so is not natural according to the WBF's definition.

In England our understanding is somewhere in between. The old Orange Book (pre-2006) summed it up quite well: a natural suit bid was

a bid of a suit which shows that suit and says nothing about any other suit. ...

So a Muiderberg 2S opening is not natural, because it shows length in another suit (even though that suit is unspecified). But, unlike with the WBF's definition, it is still possible for a natural bid to be conventional. We would say that the opposite of natural is artificial. An example of a bid which is conventional but not artificial is a 1D opening which promises an unbalanced hand. This certainly shows diamonds, and says nothing about any other suit, but there is an additional agreement about the hand as a whole which makes it conventional.

Because I learnt my bridge in England, this is the definition which feels most right to me (and not just because I'm an avid reader of Orange Books! - this really is what people mean by "natural" in England, give or take some of the details). Unfortunately, both of the conditions in that old OB definition are slightly faulty.

First of all, what does it mean to "show that suit"? The old OB definition continued:

The suit shown will be at least four cards before opener rebids but may be three cards from then on; exceptionally a bid of 2C in a 3=4=3=3 hand precisely in response to 1S is considered natural.

This definition appears to make bids such as 1H (pass) 2H artificial if they could be made on three cards. In practice, this oversight was just ignored - no-one was suggesting that these bids should be alerted - but it did look a bit silly. It was corrected in the new version of the OB, where the definition of a natural suit bid is:

A bid of a suit which shows that suit and does not show any other suit; the suit shown will be at least three cards long except that preference bids and raises may be on shorter suits. Note that in earlier rounds of bidding a natural suit bid usually shows at least four cards.

This is a much better definition of what it means to "show" the suit bid. It's also an improvement for the bids which show only three cards suit. According to the old OB defintion, a 3-card 1H opening was alertable because it was not considered to be "natural". But this doesn't seem right - it surely is a natural bid, but ought to be alerted because it is unexpected.

The second part of the definition is much harder to get right, and neither of the two EBU versions really works properly. According to the old regulation, a natural bid should "say nothing about any other suit". Presumably this was discarded when it was realised that nearly every natural bid shows something about the other suits, even if this is only from the negative inference that some other natural bid could have been made instead. And, for example, a pre-emptive opening bid which is played as denying a side 4-card major should still be considered to be natural. But the new version goes too far in the other direction, so that (for example) a 3H bid which shows heart length and club shortage is considered natural. This isn't a problem for the alerting regulations because club shortage is still unexpected, and therefore alertable, but it doesn't correspond to what we really think of as being "natural". I think the old definition is closer to the truth here, and they just needed to make an exception so that a bid could still be natural if it denied a certain amount of length in another suit (or suits).

Still, there isn't really any obvious way to define it perfectly, and it's interesting to see how various different authorities try (and fail) to do it. And that's without even considering what a "natural" no-trump bid should mean.