Don't Hesitate!

This post is about the laws on Unauthorised Information, and in particular the definition of a logical alternative (Law 16B1(b)).

Here in England, we used to have a "70% rule" for logical alternatives - that is, if a particular action would be chosen by more than 70% of a player's peers, then we would say that there were no logical alternatives to that action.

The "70% rule" no longer applies: it has been superseded by the definition provided by the new (2007) Laws. That is,

A logical alternative action is one that, among the class of players in question and using the methods of the partnership, would be given serious consideration by a significant proportion of such players, of whom it is judged some might select it.

Since this is now part of the Laws the EBU is obliged to go along with it, though there is still room for interpretation - particularly in terms of quantifying what is meant by "a significant proportion" and "some". The EBU suggests "a significant proportion" is something in excess of 20%. I'd have to say that to me the term "significant proportion" sounds more like 30-40%. But that's not the main point here. Whatever the details are, it is clear that this definition is going to result in there being many more LAs than there were under the 70% rule (since "some" is a lot less than 30%). To put it another way, the Laws are now much more restrictive in terms of which actions you can take when in possession of UI.

What are we to make of this? If we look at it from a TD's point of view, we just have a different test to apply. That's not so hard. But how about from a player's point of view?

It seems to me that we will have to start looking at UI situations in a different way. And particularly if we are talking about UI from hesitations.

It is often said that inadvertently transmitting UI is not an infraction: the infraction is if you make use of information from partner. It is advisable not to hesitate as this may put partner in a difficult position, but if you find that you have to think then you should not worry too much, because if partner has a clear-cut action then he will still be able to make it.

Now, in theory this position has not changed under the new Laws: it is not an infraction to transmit UI. However, I believe that this is no longer the right way to think about it. In my opinion, the effect of the new definition of a LA is that there is now a penalty for hesitating. Not the automatic penalty advocated by Bobby Wolff, but a randomly-applied penalty that depends on the other hands at the table.

The thing is, the definition of a LA is now so weak that there are all sorts of rubbish actions that have become LAs. It's no longer good enough for you to have a clear-cut action, it has to be very very clear-cut: it has to be obvious to all those idiots that the TD believes are your peers (though of course you are really a much better player than they are). Think about all the silly bids made each day: it doesn't take much for there to be "some" people selecting an action.

So, if you hesitate in a tempo-sensitive situation, there is a fair chance that the TD will have to impose some daft action on your partner. It's no good blaming the TD for this, since he has to follow the Laws. And you certainly can't blame partner. No, it's your fault for hesitating.

Like I said, I view this as a change. With the 70% rule it was best to avoid hesitating, but even if the TD did have to adjust the score you could be assured the result would be fair: you would not be given a silly result. This is no longer true. There is a penalty for hesitating, and depending on the hand that penalty may well seem very arbitrary to you - it is quite possible that you would genuinely never have had that result with or without UI. So, you must not put yourself in the position where that penalty can be applied.

If you hesitate and it happens to make no difference, then you are lucky. If you hesitate and find that the TD has to adjust to some silly result, that's your penalty for hesitating. So don't hesitate. Or at least, if you hesitate, then be prepared to accept your penalty.

Update

OK, so I haven't done any blogging for ages. In fact, I haven't been playing much bridge at all recently. Back in the summer I was finishing off writing up my PhD. After that I moved back to Hampshire - unfortunately away from most of my bridge partners. I expect I'll be moving again once I've found employment ... but who knows how long that will take. (In fact I had my first interview last week; actually I'm waiting to hear back from them in the next few days, but let's just say I made a few mistakes that I can learn from there.)

Meanwhile, I've been playing a bit of bridge with my Dad and his group of friends - in fact we won a little swiss teams event last month - but it's not quite the same as when I was in the U25 squad.

You might think, if I'm unemployed and not playing much bridge, I'd have plenty of time for blogging. Why hasn't it turned out like that? Well, I think many people have found with this sort of thing, it's difficult to keep up the initial enthusiasm. And particularly for me, since this is a bridge theory blog and not a bridge hands blog (because this is what I find most interesting), I don't get a limitless supply of material just from playing the game. I started this blog to get certain things off my chest - particularly my thoughts on bidding theory. And now I've said what I wanted to say there.

But every so often I find things that make me want to write a blog post, so I'm not going to stop completely. Unfortunately a lot of these things are about bridge politics, which can be interesting but is not particularly uplifting. And I'm worried that if I talk about bridge politics too much you'll get the impression that I think bridge administration is in a mess, which is not the case at all. Never mind. There will doubtless be a lot of bridge politics on this blog, but I hope I can find other things to talk about as well. I have a few things lined up, let's see how it goes ...

L&E Minutes for June 2008

Apologies for the excessive amount of EBU stuff on my blog, but we live in interesting times ...

6.2.1. New permitted agrements at Level 4.

So we have some new "toys" at Level 4. They are all pretty harmless, being things that it makes sense to allow given what is already permitted. For example, in the rule for "Either-Or Club" both the strong option and the weak option now correspond properly to what is allowed at lower levels.

6.2.2. 2C Fert.

This is the evil convention from Brighton where 2C shows 0-5 points with either 4+ spades or 4+ hearts or 4+ diamonds. The L&E decided that they didn't like the way this could be opened on a two-suiter with longer clubs. So they've banned this.

I'm not sure this makes a whole lot of difference. This change doesn't really affect the defenders' options. And there are other hands with longish clubs that could still be included by modifying the definition slightly - for example it seems a pair could still play 2C as "any hand except for a two-suiter with clubs as the longest suit".

The problem is these ferts should never have been allowed in the first place - not when Level 4 is to be used for nearly all EBU events. The pre-2006 rules defined the permitted methods in terms of one-suiters, two-suiters and three-suiters. This might have looked a little clumsy but it did at least mean you ended up with bids that actually had a definition. With the 2006 rules, if you want to get around the requirement not to include the suit bid in the "specification", you can do this simply by not specifying anything much at all! These things should not be allowed: the EBU should be requiring a minimum amount of "specification" like the pre-2006 rules did. This would still be considerably more permissive than, say, the WBF "Brown Sticker" regulations.

6.2.3. Alerting of doubles.

Good news here: the L&E discussed three decent options, and decided to go with this one:

Alert strange doubles only at any level. Any double that is takeout, penalties or somewhere between the two is not alerted.

In my opinion this is not only the best of the three options discussed, but indeed an excellent solution to the problem. Finally, after about three years of discussing this, the L&E has found something which will actually work. I'd really prefer there to be an exception for doubles of natural opening bids (a double of a suit opening is expected to be for take-out) but that is a relatively minor niggle.

The bad news is that this now has to be approved by a new committee of the EBU, the "Club Committee". Now don't get me wrong - I think it is perfectly right that clubs should have an input into this process. But now is not the right time. The views of clubs should have been sought during the initial period of consultation - in fact they were, I believe, though if the EBU's committee had already been set up at that point then perhaps the consulation could have been done more effectively through them. But when it comes to a final decision, that ought to be solely the job of the L&E. The L&E is perfectly capable of taking into account the needs of its club players when making its decisions; in fact, while I can't speak for the committee, I am quite sure that this has always been their number one consideration.

Instead, having already put up with the awful 2006 rules for two years, the implementation of the new rules is being delayed by at least another few months, despite the fact that we already know what they should be. And this is all assuming that the Club Committee actually approves of the idea. The real reason why you shouldn't have two committees looking at the final proposal is what happens if they come to different conclusions? Then the L&E would be faced with either not being able to implement what they know is right, or pushing it through and having it look like they aren't listening. It's just not good political sense to put yourself in this position.

But no complaints with our elected members here, since it was evidently not their decision.

6.2.4. Rewording of OB 3E.

This is the section on how asking questions can transmit unauthorised information. England has a reputation for being much harder on this than other countries. The new wording doesn't do much to change this, except in the case of asking about doubles:

3 E 2 Questions asked during the auction about the meaning of an opponent's double shall usually not be considered to pass Unauthorised Information, nor to have the potential to mislead declarer about the questioner's shape or values. However, the TD may still use his discretion to give an adjusted score if the nature of the questioning clearly provides partner with unauthorised information.

Presumably this is linked to the proposed change to alerting (it wouldn't make much sense with the current rules). I am very happy with this new wording. But it does seem oddly inconsistent with the rules for other situations. Why say this about doubles but not about alerted bids, or bids above 3NT? I think there is a better case for saying "questions about alerted calls are usually not considered to pass UI" than there is for saying the same thing about doubles.

Busy Week

It certainly has been a busy week. First of all for me personally: in a few days' time I'm going back home for my dad's birthday, and before I leave I really need to have finished a draft of the main section of my thesis. So, as you can imagine, I've been working pretty hard. On a similar note, congratulations to my friend David Hodge who submitted his own thesis down in Cambridge on Monday.

In the bridge world, there was the vote on the EBU's strategy proposals at Wednesday's EGM. The proposals were voted through, with 52 in favour and 31 against, meaning that Pay-to-Play is to begin in 2010. As you know, I think this is misguided. But I'd like to echo what Jeff Smith said at our county's AGM which took place the following day: now that the proposals are a reality, it's important that everyone helps to make it as successful as possible. If the proposals are implemented well, then it may be unpopular but the EBU will survive. But if mistakes are made there is the potential for disaster. I would have to say that in the past the EBU has been very bad at communicating its ideas, even the good ones. This can't be allowed to happen for something as important as these changes. The number of clubs that have said they would disaffiliate is really quite shocking, particularly here in Manchester and in my home county of Hampshire. I hope that many of these clubs can be persuaded that they should remain a part of our NBO. I'm sure that some of the objections are things that could be overcome by better understanding.

Thursday was the first time I'd been to my county's AGM. It took three-and-a-half hours, but actually I was quite impressed by the relatively small amount of pointless argument. My contribution was to suggest that, in order to try to reduce the number of teams who withdraw from the first round of the cup without playing their scheduled match, teams should not be allowed to enter the plate unless they actually played their first-round cup match. (Teams do have the option of entering straight into the plate, if they do not want to play in the cup.) Apart from this I managed to keep quiet, and avoided being given any jobs to do (having the excuse that I may be leaving the county at the end of the summer).

Also on Thursday was a meeting of the L&E. It appears that they have made a decision concerning the alerting of doubles, but details have not been made public yet. Mr Stevenson said that before being adopted it would have to be looked at by the new "Club Committee" of the EBU. That's slightly scary since I get the feeling a widely held "club" view is that everything the L&E tries to do is wrong; but perhaps we can hope that an official committee would be more constructive. Anyway, it looks like some progress has been made.

Why I Oppose the EBU's Strategy Proposals

The EBU exists to promote and organise the game of bridge in England. It is the "promotion" part that we are interested in here. Bridge is a great game: the more people that play it the better. If the EBU can do something to increase the number of people playing then they can rightly say that they are a successful organisation. In fact it seems that the number of people playing bridge is declining; the EBU is understandably worried about this and is trying to do something about it.

But let's be clear about this - what we care about is the total number of people playing the game, whether or not they are members of the EBU. The success of the EBU is not defined by the number of people they have on their membership list, but by the total amount of bridge being played in the country. That's what it really means to promote the game.

The core idea of the EBU's strategy proposals is for "universal membership" - that is, all members of EBU-affiliated clubs would automatically be members of the EBU. Even if a large proportion of clubs decide to disaffiliate, this proposal will still surely increase the number of EBU members. But will it actually do anything to stop the decline in the number of people playing the game?

The most controversial aspect of the proposals is that they would change the way the EBU is funded. Rather than having an annual subscription, the proposal is to charge players a certain amount for each session of bridge that they play, taken out of the table money. The intention is for the scheme to raise the same amount of money as the current scheme does; however, if you consider individual players, there will inevitably be some players for whom bridge becomes more expensive to play, and some for whom bridge becomes less expensive.

The way things are at the moment, with the annual subscription, means that the EBU membership contains a disproportionately large number of tournament players and other keen players, compared to the bridge-playing population as a whole. So, in effect, the tournament players are subsidising the rest of the bridge-playing population. Under the proposed Pay-to-Play scheme everyone would be contributing. The net effect is to make bridge more expensive for the casual player; their money goes to make bridge less expensive for the serious players. Isn't this a bad thing if we want to promote the game? The keen players are going to continue playing whatever happens. We want to get more people playing the game, but the newcomers are the people who are worst off under the proposed scheme, since at the moment they would tend not to join the EBU until they are more experienced.

My opinion is that the keen players should subsidise the promotion of the game, like they do at the moment. Because I enjoy playing the game, I am keen to see other people learning to play, and I am very happy for my money to be used to get them started. Under the EBU proposals you would instead be taking disproportionately large amounts money from the very people who you are trying to promote the game to. Admittedly the amounts of money involved are quite small, but one of the attractions of the game is that it ought to be a relatively inexpensive hobby. When the table money is typically £1.50, an increase of 30p or so is noticeable.

There is a strange imbalance in the EBU's proposals: having scrapped the annual subscription, they intend to make up for this almost entirely with Pay-to-Play fees from club games. But, as I said, most of the people playing annual subscriptions at the moment do so because they play in county or EBU events. So surely a sizeable proportion of the new Pay-to-Play fees should be coming from tournaments. But for some reason they are not doing this. Instead it is the casual player who pays more. I don't understand this at all.

But really it is not so much about the money anyway. People have strong feelings about the element of compulsion. If people currently are not members of the EBU, that's because they don't want to be members. If you force people to join an organisation that they don't wish to belong to, then that is surely going to be very unpopular. The fact that they have to pay for the privilege just makes things worse.

Let's face it - very little of what the EBU does actually benefits its members directly. You don't need the EBU in order to have a game at the club. But as a national bridge organisation, the EBU has some important obligations. The obvious example, and the most expensive, is sending teams to (and occasionally hosting) international events. Money is also needed to promote the game. These are good causes, and I have chosen to help fund these things through my subscription. But other people might not value these things so highly. That's unfortunate, but it should be their choice to make.

The EBU already tends to get a rather bad press. There is a significant group of players, including both members and non-members, who are distrustful of the EBU, generally feeling that it interferes with the game without giving them anything of value. Some feel that the EBU concentrates too much on serious players at the expense of the ordinary club player. Issues such as the introduction of announcements in 2006 proved to be very divisive. Generally I do not think the EBU deserves the criticism it gets, but I worry that the introduction of compulsory membership for players at EBU-affiliated clubs will only add to the antipathy that already exists. The critics will see it as just another way in which the EBU is trying to impose its influence on people who do not want anything to do with it.

While the details of the proposal have been well publicised, it has been quite difficult to find out why they want universal membership. The reasons that have been given seem mostly spurious. I went along to a discussion at the Brighton congress to hear what they had to say. Mr Capal pointed out the fact that the EBU membership was made up of disproportionately large numbers of serious players, and that universal membership would make the EBU more representative. This is absolutely true, as I have already said above. But Mr Capal's suggestion was that the EBU would not be able to address the needs of the casual club players unless they were members. This is utter nonsense. Of course the EBU should be listening to the club players; they should find out what these players want from their NBO and make sure that the EBU works for the benefit of everyone. But this has absolutely nothing to do with whether those players are members. The EBU should be working for all the bridge players in England, whether they are members or not. If the EBU has in the past ignored the large body of bridge players who are non-members, then that is a terrible failing. But it is something that can be put right. And it certainly has nothing to do with the way the EBU is funded.

I was particularly unimpressed by the long list of things that the EBU would provide for its clubs. Perhaps the most interesting idea was the proposed new "ranking" scheme, but there were also more mundane things like free software. Now, there was nothing wrong with any of the things on that list. But again, the problem is these services have nothing to do with the way the EBU is funded. The EBU should always be seeking to improve its services to clubs, but you don't need to impose universal membership in order to do this.

Finally, and only quite recently, the EBU did present one valid reason for universal membership. If the EBU has more members, then it can potentially get more money from sponsorship and advertising (particularly from the members' magazine), and could have more influence as a political force. It's quite depressing to think that what is basically an accounting trick ("in order to get more members, we'll just redefine who is a member") could actually make a difference to the influence the EBU has. Perhaps this is how the world works. But personally, I do not believe that this advantage is enough to make it worth alienating all the bridge players who do not want to be members of the EBU. I don't think the EBU is a popular enough organisation to get away with forcing people to join. Even the EBU itself is anticipating a mass of disaffiliations if the proposal goes ahead.

The final vote on the proposals is taking place in three weeks' time. It will not be the end of the world if the proposals are voted through. But if the EBU really wants to get more people playing bridge, there are plenty of things it could be doing to help achieve that - and these things have nothing to do with universal membership or Pay-to-Play. And for an organisation which already has trouble with public relations, the proposed strategy will only make things worse.

Everyone Needs a Forcing Raise

This is not really a bidding theory post, it's more of a practical thing.

In my regular partnerships I play very complex systems. But I also play with lots of different people from the club, and then we play simple versions of Acol. Now, I'm not a big fan of Acol, but if it's just for the odd evening I don't really feel I miss anything from my more complex systems ... except for one thing.

Traditional Acol has no bid which shows a forcing raise of a suit opening. If partner opens a major and you have a game-forcing hand with 4-card support, you are supposed to start by bidding a new suit, and then support partner at game level on the next round (a "delayed game raise"). With a very strong hand you might have to start with a jump-shift. (These days splinters have become very popular - widely understood even at the club - but they don't help you when you don't have shortage.)

The problem is that this just doesn't seem to work. Either you or your partner has to guess whether to go past game, and my experience is that it is very difficult to guess well. In order to have a sensible auction, you really need to tell partner that you have a game-force with support before you reach game level. So, you need a forcing raise.

For me this really became very evident in the last few weeks. I saw six hands suitable for a forcing major-suit raise - three in a beginners' class, two in the club duplicate and one in a league match. Of these, there were two missed small slams, one grand played in game, one poor slam going off and one hand played at the five-level with three losers. Only one time was the hand bid to the right contract. But in each case where it went wrong you couldn't say anyone had made an obvious mistake. And in each case the hand would have been trivial to bid with a forcing raise (apart perhaps from the grand slam, which might only reach six).

So it's clear to me now: if you have a new partnership - even for just one evening, and no matter who your partner is - you have to agree a forcing raise. Forget about defences to 1NT or other such trivial matters. You can do without those. You can't do without a forcing raise.

This applies even to beginners. Generally you would like to teach a beginner basic natural methods, leaving any unusual conventions to people who have reached a more advanced level. But for raises it's totally the opposite way round. A beginner is hopelessly lost without a bid which shows this hand, whereas it takes expert judgement to play delayed game raises. This is a rare example of how adding a convention actually makes the game much easier to play. Club players are often criticised for using Blackwood too early in the auction; but in many cases this is because they have no reasonable alternative. If they haven't been taught a forcing raise, what else would you expect?

The good news is that the EBU's teaching methods now appear to be recommending 3NT over a major-suit opening as a "pudding raise" (showing a raise to game without a shortage to splinter in). But this hasn't yet permeated through to the ordinary bridge player in the way that splinters have. A pudding raise is excellent for beginners or for a one-off partnership, though it doesn't solve all problems and so a lower forcing raise would be preferable (but requires more complicated responses). When I played with David H at Cambridge we thought we couldn't afford to give up our natural inviatational 2NT response (I might have a different opinion now!) and so we used 3C as a raise instead. We started winning IMPs every time it came up. I've never seen a convention which made such an immediate improvement to a system as this one did.

This was all assuming a major-suit opening. And indeed it is more important to have an artificial raise for the majors than for the minors. But this is only because of frequency: with, say, 4-4 in a major and a minor, if partner opens the major you need to raise immediately, whereas if he opens the minor it's more normal to bid the major-suit first. Thus a minor-suit raise is only really needed when we have a single-suited hand - but when this does come up it is no less important than it was for the majors. In a simple system I might like to use a jump in the other minor as a game-forcing raise. Admittedly, when it comes to the minors, if you're playing in a one-off partnership you might just hope it doesn't come up. That wouldn't work for the majors though.

I've heard some traditionalists say that you can get by without an artificial raise. Perhaps you can, just about, get by. But as I said, it takes expert judgement to play delayed game raises with any sort of effectiveness. And if you then go and look at the systems the experts are actually playing ... they are unanimous that an artificial raise is a good idea.

So my conclusion is not so much that it's nice to play a forcing raise - because I'm sure you knew that already - but that if you have a beginner who is learning Acol, or a new partner who plays old-fashioned methods, this is one thing you really must add to their system.

Stayman v. Keri

Keri is Ron Klinger's system of responses to a 1NT opening, as described in his book "Bid Better, Much Better After Opening 1NT". I played this in my partnership with Mark. But since then I've gone back to ordinary Stayman, and in this post I'll try to explain why.

In Keri a 2C response forces opener to bid 2D. There are then three basic sequences which take care of the hands which would have bid Stayman in standard methods:

• 1NT : 2C , 2D : 2M shows an invitational hand with 4 or 5 cards in the major.
• 1NT : 2D , 2H : 2S shows an invitational hand with both majors. (The 2D response in Keri is a transfer to hearts, but differs from a standard transfer in that in can have only 4 hearts if it is invitational with both majors.)
• 1NT : 2C , 2D : 2NT shows a game-forcing hand.

The first of these sequences is the one we need to focus on, since it is the only really fundamental part of the system. (There are variants of Keri which deal with game-forcing hands differently to the "book" version above.)

The idea is that after 1NT : 2C , 2D : 2M opener will pass with a minimum hand with 3 or 4 cards in the major. Thus a big advantage of Keri is being able to stop in 2M - particularly when this is a 4-4 fit (where a Stayman auction would have reached 3M after 1NT : 2C , 2M : 3M) or a 5-3 fit. There are plenty of examples of this in the book. The disadvantages, on the other hand, are not so clearly spelt out!

The main problem with the 1NT : 2C , 2D : 2M sequence is the ambiguity in responder's major-suit length. It could be either 4 or 5 cards - and having to cater for both is a little uncomfortable. In particular, it makes a difference to the the type of hand on which opener wants to accept the invitation. When responder has only 4 cards in the major he is mainly interested in whether opener is minimum or maximum in high cards. But when responder has a 5-card suit, fit tends to be more important. In an attempt to cater for both types, Keri uses a 3C bid by opener to show a minimum with good fit - but of course when you do this you are losing the chance to play in 2M, which was supposed to be the advantage of playing Keri. And in any case this still doesn't solve the problem that there can be a big difference between 2- and 3-card support when responder has 5-cards, but there isn't when responder has only 4.

Another issue is that you frequently play in a 4-3 fit. Opener passes the 2M bid whenever he is minimum with 3-card support. As Klinger's book points out, this often works quite well. But it does rather depend on the hand. Playing a 4-3 fit looks great when responder has a good suit and opener has a weak side-suit doubleton. It looks rather less clever when responder's suit is bad and/or opener is flat. The difference is highlighted at matchpoints where you are going very much against the field (and if 2M makes the same number of tricks as no-trumps you will score badly). Unfortunately the system forces you to play 2M every time. So you end up with some good results and some bad results. Klinger's book seems to be trying to persuade us that it is a winner on average; this wasn't my impression from playing it.

There is no doubt that when responder has a five-card suit and the invitation is rejected, you are pleased to be able to play in 2M. But here Stayman can be even better than Keri, at least when the suit is spades. Playing Stayman we can use 1NT : 2C , 2red : 2S to show an invitational hand with 5 spades. When this comes up we get all the benefits of Keri but without the ambiguity about spade length. As mentioned above, this helps opener in knowing when to accept the invitation. But, even better, it means that opener can pass with a doubleton. A 5-2 fit does tend to play better than no-trumps, particularly if responder is unbalanced. In Keri you have to bid 2NT over 2S with a doubleton spade, in case responder has only four. But when responder has a 5-card suit you would generally prefer to play 2S in the 5-2 fit rather than 2NT.

This is not available when the suit is hearts. If we play Stayman we have to start with a transfer on an invitational hand with 5 hearts. My preference is that opener should be keen to super-accept with a good heart fit, so when responder has a borderline invitation he should transfer and then pass 2H. This can also work better than Keri on those hands (since we play 2H rather than 2NT opposite a doubleton). On the other hand, a sound, fairly balanced invite with hearts is certainly better bid in Keri.

One nice thing about Keri is the continuations after a transfer: because 2NT is not needed as invitational, it can be used to improve the game-forcing sequences instead. However, this is not really an advantage of Keri since it can also be easily incorporated into a Stayman-based system. Playing Stayman-then-2S as an invite frees up 1NT : 2H , 2S : 2NT just like in Keri; and if we are playing Stayman we don't need to use 1NT : 2D , 2H : 2S for 4-4 majors like Keri does, so there is plenty of room here as well.

There are more problems if you play the "book" version of Keri. One that particularly bothers me is that while Stayman is notorious for giving away information to the opponents unnecessarily (when opener shows or denies a major that responder is not interested in), Keri is, if anything, even worse in this respect. After 1NT : 2C , 2D : 2NT opener reveals whether or not he has a doubleton, even though this information may not be needed by responder. A similar thing happens after 1NT : 2C , 2D : 2M if opener has enough to accept the invite. Against opponents who are good enough to make use of the information this is a very bad idea.

Finally, you do need to think carefully about how you will cope with interference, and the book is a little short on detail here. I remember once, after bidding 2C and hearing a 2S overcall, not being sure whether 3D would now be weak or invitational. (It may not even be possible to distinguish.) In the Junior Camrose this year a player responded 2D to 1NT on an invitational hand with 5 spades and 4 hearts, and then heard a 2S overcall! This should have gone for a four-digit penalty, but instead they had a misunderstanding and ended up in a silly contract. A transfer which only guarantees 4 cards does tend to cause problems in competition even if you are well-prepared. More generally, you'd better be sure you know how much of the artificiality applies in a competitive auction. This significantly increases the amount of work involved.

My conclusion is that while Keri is a decent alternative to Stayman, it certainly isn't "Much Better" as the title of the book claims. Perhaps the best thing about the system is that if you and your partner both know the book, you can agree "Keri" and immediately have a complex, rather effective system ready to go, without needing to develop it for yourself. But, in my opinion, if you had a book which was based on Stayman that could be even more effective.