IAC Forums
Chew the Fat! => The IAC Café => Topic started by: Curls77 on March 10, 2019, 08:56:25 PM
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If I am not wrong, when Hondo was teaching in IAC, and so altruistically kept lessons online to help me, and alikes me learn the game, he took extra effort to explain that Gerber occurs in only 2 occasions: jump to 4C after 1N or 2N opening, be that direct or thru 2C.
But, in our treasure box, which are IAC Spur matches, this bidding happened, red aga white:
1S-2D
2N-4C (Gerber, asking for Aces)
4H (one) - 6N
which went down 2.
Opener: QJ743 AKJ 76 Q85
Resp: -- T82 AKQT543 AK4
So my question is simple: having in mind that 2N rebid from opener can show really just minimum, can responder use Gerber there? And with that kind of hand? Asking Aces with void?
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I would play that 1 !S - 2 !D - 2NT - 4 !C is Gerber. Now whether it's a good idea here or not is a different issue. If I am understanding the hand diagram correctly, declarer has seven diamond tricks to go with three clubs and two hearts, so that's twelve tricks once he gets the lead. So indeed, controls are the issue. Is that T82 in hearts or spades? If the void is in spades, seems 6 !D is making.
Dinner was on, but now I will expand a bit.
As with any convention, if you are going to play it you have to agree when it is on and when it is off. I play weekly, more or less, with Carl (not a BBO player). Our agreement is that 4 !C is gerber if it is a jump made directly after a natural NT bid. So: 1 !S - 2 !D - 2NT - 4 !C is a jump to 4 !C over the natural rebid of 2NT. That makes it Gerber for us. I have been playing it that way more or less forever, and most everyone I know plays it that way also. In a regular partnership there could be further rules. For example I have played that 1 NT - 2 !C -2 anything - 4 !C is Gerber. It's a jumpe, and it's over a natural NT where first you trotted out Stayman. But I would not try it without discussion. A jump to 4 !C over a natural NT, whether an opening or a rebid, seems likely enough to be taken as gerber. Most play it that way, and what else would it be? If, after 1 !S - 2 !D - 2NT I wanted to show !C, I would bid 3 !C. Of course you could specialize it so that 1 !S - 2 !D - 2NT - 4 !C is strong 5-5, or you could specialize it as an auto-splinter trying for a !D slam with a stiff !C, but those are a bit exotic and so, without discussion, 1 !S - 2 !D - 2NT - 4 !C would seem to be gerber. (I corrected a couple of typos)
The fact that opener might be minimal for hos 2NT rebid is not an issue. Opener's hand is confined to a small range (well, until we hear differently) , but resppnder's hand is not so restricted. He can have a hand where he thinks a slam is likely opposite opener's minimum, and he just wants to kow if the opponents can take two tricks first.
Were the !D splitting 4-0? I can't see how else he goes down 2. Responder needs to worry about opps cashing AK, but he is not expected to worry about running diamonds after opener rebids 2NT and he holds AKQTxxx
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Gerber.
Not a huge fan. It is overused and abused. There are many auctions where it could be used, but without specific agreement I prefer to keep it painfully simple. With a random partner, assuming we have little to no discussion, Gerber is only a jump directly over a 1NT or 2NT open (or 2 !C - 2 !D - 2NT). There are too many other viable (better?) uses for the jump to 4 !C .
For example, in this auction: 1 !D - 1 !S - 1NT - 4 !C I prefer to use the jump to 4 !C as an auto-splinter. I think it's a more valuable use for it. I would also guess it is treated as an auto-splinter by most experts, but I have no data to back that up.
Or this auction: 1NT - 2 !C - 2 !H - 4 !C. Playing Baze (a common treatment), 4 !C is RKC for !H . This is BWS2017. I prefer Modified Baze where 4 !D takes the place of the keycard ask (this is theoretically better as it preserves a little space for controls). Not playing some flavor of Baze, it's pretty universal to play a 3 level rebid of the other major as agreeing trump. So 4 !C would then be available as a splinter agreeing trump. Again, eschewing Gerber.
Of course there are other instances where I have seen 4 !C alerted as Gerber. The one that pains me the most if over a natural 3NT. Slam going? Certainly. A control? Possibly. Gerber? No way.
I think we could go back and forth about Gerber for pages and pages. There are just too many possible auctions where it might be used. But that is exactly why I prefer the simplest "hardly ever" treatment.
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Regarding the IAC Spur Match hand; opposite a random partner I would have guessed it to be Gerber.
Would I have used Gerber there? No. Getting the response of one ace, how high do you go? It's not really helpful.
That said, with a practically solid seven-card !D suit, playing IMPs, I would never choose to play in anything other than !D .
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It still isn't clear to me if the void is in !H or !S but I will assume:
!S: QJ743
!H: AKJ
!D 76
!C: Q85
!S: Void
!H: T82
!D: AKQT543
!C: AK4
After 1 !S -2 !D - 2NT -? It is perhaps reasonable to expect there to be 12 tricks if they don't take 2 first. But how to tell? With natural bidding it seems that it could go:
1 !S -2 !D - 2NT - 4 !D, That would set diamonds as trump, and then I see if partner bids 4 !H. If he does, I bid 6 !D. If he doesn't, I bid 5 !D. It's true that having him hold the A doesn't guarantee I make the slam, and it's also true that the slam might make if he holds KQx, but I would not try to unravel all of that. If he has the !H A I want to be in 6 !D.
A reasonable approach is that an undiscussed bid is natural if it makes sense as natural. A sequence that could be natural but isn't should have prior discussion. W/o the discussion, it's natural. So, after 4 !D, pard bids his !H control if he has it. The above hands are making 6 !D unless the distribution is very unlucky. Even a 4-0 !D split is ok of the !D length is to the right. If it is to the left then you are only getting six !D tricks. Maybe the !H J will score to bring the total to 12. . 6 !D is a fine contract.
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YUCK to Gerber, but ty for your answers; it really helped me understand. But I do find very strange what Ken says " 4C as a jump made directly after a natural NT bid". Rebid of 2N is often forced, as was in this deal, there might be nothing natural about it.
Full deal: https://tinyurl.com/y5kxygmh
So, nag to both, and tip to running mentors, how about give a session on when we ought ask for aces? so many seem not have that figured.
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YUCK to Gerber, but ty for your answers; it really helped me understand. But I do find very strange what Ken says " 4C as a jump made directly after a natural NT bid". Rebid of 2N is often forced, as was in this deal, there might be nothing natural about it.
Full deal: https://tinyurl.com/y5kxygmh
So, nag to both, and tip to running mentors, how about give a session on when we ought ask for aces? so many seem not have that figured.
The 2NT re-bid was natural. After 1 !S - 2D opener is forced to bid, that's true, and he should make a natural bid. With 5=3=2=3 shape and a 13 count, 2NT is very natural. It suggests a reasonably balanced hand and 12-14 points (or, on occasion, 18+, but responder assumes 12-14 until he hears differently). Besides being natural, it is informative. Opener will to always have exactly that shape but he will have approximately that shape. This allows responder to have a reasonable idea of where the hand should be played. With long diamonds and good values he might well think that there are 12 ricks as long as the defenders do not take the first two. Indeed this is correct unless there are four diamonds on his left.
This does not necessarily mean that Gerber is the best choice, just as RKC is not always the correct choice after, say, 1 !H - 2NT (Jacoby). When holding a void, Gerber is apt to be the wrong choice, just as RKC would be the wrong choice for opener after 1 !H - 2NT. So Gerber is a bad choice here.
I don''t share the frequently expressed disdain for Gerber. Used correctly, I have found it useful. Don't use 4NT RKC with a void, don't use 4 !C Gerber with a void, that's a good start. But with sensible use, it's useful.
What do you have in mind when you say that the 2NT re-bid is not, or might not be, natural? It's not strong, but it's natural.
Here is a starter rule for when not to ask for aces: If the answer that you get will not allow you to decide where to place the contract, then look around to see if maybe something else will. As mentioned, in the case at hand I would like to start a cue bidding sequence with the idea that if partner can cue hearts, I will bid 6 !D. If he cannot cue bid hearts, I will bid 5 !D. It's not that I will be certain of just how many tricks I can take, but I can control spades by ruffing, I cannot control hearts, so I am interested in whether partner can control hearts.
Note that as long as you are playing in !D, you can still make 6 !D even though you will, very unluckily, be losing to the !D J. There is no way you can find out exactly what partner has, and there is no way you can find out that !D are splitting 4-0 iwith the wrong hand holding the length, but you can learn that partner has the !H control, after which 6 !D is apt to have a play. That's all you usually get to know, that a contract should have a reasonable play.
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I don''t share the frequently expressed disdain for Gerber. Used correctly, . . .
But that's my problem with it. "Gerber" and "Used correctly" seldom collide in the same conversation.
It seems everyone has their own ideas for when it is, or is not, "on." It's required to have a conversation about it. With no time for discussion, it's the simplest interpretation.
With a random partner, assuming we have little to no discussion, Gerber is only a jump directly over a 1NT or 2NT open (or 2 !C - 2 !D - 2NT).
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Probably best to stick to the basic version if not discussed.
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For Ken: imagine someone opened: KQJxx xxx x AQxx. And bidding is 1S-2D-? Would they rebid 3C? And if hand was KQJxx xx xx AQxx is that "natural" 2N? Sorry if I ask stupid questions, but most of us that supposedly "learnt" game recently, and online, are not best friends with natural bidding.
Then another problem follows: answers to Gerber? I was taught 1-4 3-0 2bad 2good. uhuhuh, i don't think i ever saw anyone play that? and it's certainly nothing we'd discuss as new pardships at start of iac spur match.
But that's my problem with it. "Gerber" and "Used correctly" seldom collide in the same conversation.
It seems everyone has their own ideas for when it is, or is not, "on." It's required to have a conversation about it. With no time for discussion, it's the simplest interpretation.
With a random partner, assuming we have little to no discussion, Gerber is only a jump directly over a 1NT or 2NT open (or 2 !C - 2 !D - 2NT).
Fully agreed here :)
And another appeal to mentors and teachers, that was real ground of this question, which Ken did explain nicely, but many do not read forums. We ought remind all what kind of hands are good to use Blackwood or RKC, Gerber too. And what to do when hand is not adequate for control ask. Many play cuebids, but not all in same style.
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After 1 S - 2 !C holding KQJxx xxx x AQxx I would probably bid 3 !C. The suit is good enough.
Here is what I mean when I say that 1 !S - 2 !D -2 NT is natural. I mean that the 2NT bidder expects that often, over 2NT, his partner will bid 3NT, and he is ok with that.. They are in a game forcing auction after 1 !S - 2 !D and the 2NT suggests that unless partner has an unusual hand, 3NT seems like a likely place to play it.
Added: Maybe I'll say a little more here. Some bidding is based on agreements, such as splinters, forcing no trump, game forcing 2/1 and so on. But after that, a lot of bidding is just looking at what seems best. It would be possible, I have seen it suggested, that you could have an agreement that 1 !S - 2 !D - 3 - !C shows a hand that is 5-5 in !S and !C. But I think that's not very practical and, anyway, most people do not have such an agreement. So now look at KQJxx xxx x AQxx. We are in a game force. But which game? Since we only have three hearts, partner will usually have some. Probably the hand belongs in 3NT but of course we don't know much about partner's had so we can't be sure of that. But if I bid 3 !C and partner has, say KJx in hearts it is highly likely he will bid 3NT next. 3NT might be a fine place to play if he just has Kx, but it will obviously be best to play it from his side. If partner has nothing in hearts maybe he has Ax in spades and the hand plays best in 4 !S. What I know at the point where I must choose my second bid is that we are in a game force, partner has diamonds, I have spades and clubs. I have already bid spades, now I bid clubs. The point is that this is not any sort of convention. I have spades and clubs so I bid spades and clubs. With the second hand, KQJxx xx xx AQxx, I still bid 3 !C for the same reasons. In neither case am I really expecting to play in 5 !C, although on occasion that might be right, rather I am waiting to see, as on Sesame Street, what happens next. In these situations, different people might well make different choices, which is what makes the game interesting (or frustrating, depending). If it were all cut and dried, we would just let the robots play it.
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The sequence that always seems to give me a problem with a new partner: 1N-(M transfer)- (transfer completed)-4NT. As I learned BW and Gerber, back before the Earth had completely cooled, that is a quantitative slam try, with a postscript that responder has a 5-card Major; 4c, instead of 4N, would be Gerber. Whether asking for aces or keycards, 1430 or 0314 is another question, but every "standard" treatment I've seen recognizes 4N there as a quantitative slam try. Some use a shorthand of "first or last bid was NT," but that isn't quite accurate, either, since 4c over a natural 3N wouldn't normally be Gerber...again, whether it's a suit or a cue is a matter for further discussion.
I fail to understand the number of good players who insist they "don't play Gerber." Even if limited to direct bids over natural 1N or 2N calls (or rebids), it seems very useful to preserve 4N for a natural raise, and to keep the bidding a bit lower. The prejudice against it, I suspect, is related to the number of times their partners forget that 4d shows 0, rather than one ace...(i.e., they forget a step in the ladder; 0314 vs 1430 is another issue altogether).
I've even run into a few players for whom 4c is Gerber, regardless of suit agreement or bidding sequences: 1c-4c, for example. I can't recommend this, other than its undeniable consistency...
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in the robot indy currently underway we had an auction 1NT - 2 !D - 2 !H - 4NT - 5 !H Pass. I was the NT opener with three hearts and lacking the values to go to slam.
So just as you say.
As to 1NT - 2 !D - 2 !H - 4 !C it is possible to play that as a self-splinter. To ask for aces you start with Texas. 1NT - 4 !D - 4 !H - 4NT.
After Stayman, 1NT - 2 !C - 2M then I play (if discussed) that 4 !C is at least Gerber and I think it makes sense for it to be Key Card Gerber.
But since different people have different ideas, caution is recommended. It's good to be speaking the same language, and details matter. My older daughter spent her Junior college year in Spain. She of course spoke Spanish, but with gaps. When she first arrived she and a girlfriend visited a Madrid bar, where she ordered a pitcher of Sangre. She meant Sangria.
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Some more thoughts..Gerber goes back a long way, and I rummaged around in the basement to find Bridge Conventions by Edwin Kantar, copyright 1972!. He describes it this way.
1.Any jump to 4 !C over an opening bid of 1NT or 2NT is Gerber.
2. A response to 2 !C, Stayman, followed by 4 !C is Gerber. Eg: 1NT - 2 !C - 2 !H - 4 !C. As we have noted, now many would say it is Key Card Gerber.
3. Any jump to 4 !C over 1NT or 2NT is Gerber.For examples he has 1 !D - 2NT - 4 !C, 1 !C - 1 !H - 1NT - 4 !C, and 1 !H - 1 !S - 2NT - 4 !C.
These examples all fit into my general approach of a jump to 4 !C over a natural 1NT or 2NT.
So 47 years ago, and probably long before that, this was common usage (Kantar did not much present weird conventional agreements).
In his same book, Kantar observes that afer a 2NT opening responder has a problem if he has a club suit that he wishes to show since 3 !C would be Stayman (or, now, Puppet or Muppet or some such) and a direct 2NT - 4 !C would be Gerber! He suggests that starting with 3 !C and then, after opener's response, bidding 4 !C should cancel the Stayman message and announce that responder actually has clubs. Sometimes responder is dealt clubs, and he might want to announce that fact.
No doubt Gerber can lead to confusion, disagreements, etc, the same can be true of RKC, but the above was seen as standard by Kantar in 1972.
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4C is clearly NOT Gerber in this auction (and in truth if you agree that 4C is NEVER Gerber in any auction, you will have lost nothing). 4C here is an autocue-bid, responder agreeing his own diamond suit and making a slam try with a club control.
MS
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I mentioned a 1972 Kantar book and now I looked up the (somewhat) more recent 1998 edition of Kantar's Roman Key Card Blackwood. On page 160 he explicitly includes 1 !s - (2 !C or 2 !D or 2 !H) - 2NT - 4 !C as a Gerber auction. This does not prove that it is a gerber auction, but it does show that a preety decent player regards it as a gerber auction.
Full disclosure: Kantar and I were both born in Minneapolis in the 1930s so maybe it's a Minnesota thing. Or maybe, like me, Kantar still prefers a stick shift to an automatic transmission. Anyway.
Mostly I think my point would be that almost all conventions need discussion as to when they are n or off, and we need to go over the details of how they are played. For example, in the lesson today, or I should say the terrific lesson today, an auction began 1 !D - 2 !C - 3 !D - 4 !D - 4 !H and so on. Since 3 !D showed a self-sufficient suit, perhaps some would regard 4 !D as minorwood. Or, if they do not play minorwood there, then some would regard the 4 !H as kickback. In the auction they had, neither minorwood nor kickback was intended, or at least I don't think so. I have avoided both minorwood and kickback on the grounds that, in my experience, they are even more prone to misunderstandings than gerber. No doubt a case can be made for playing the 4 !D as minorwood, a case can be made for 4 !H as kickback, but without some detailed discussion there is apt to be confusion. I need to come to grips with various ace asking calls and this might give me the shove I need.
Which, to me, means that the lesson today was very useful. And the varied play problems that arose were most interesting! I thank you for those hands.
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Me again, in war with Gerber :-[
Yesterday during IAC Team Match, this hand happened. All red, west deals:
N: T86 A52 AKJ54 A9
S: AKQ KT98 Q8 KQ83
On both tables EW remained silent, and auctions were (alerts in brackets):
Table 1: 1N-4C (gerber) ; 4H (3? no idea)-6NT
Table 2 did not alert anything: 1N-4C ; 4D-4N ; 5D-5H; 5N
Even tho responder is balanced, should not they try for heart fit first? They know they have enough HCP for small slam, and that opener MUST have at least one diamond high honor for their opening. So why go thru Gerber?
I will risk being silly, because without idea how investigate grand, I would bid this as: 1N-2C; 2D-6N.
PS: Hope this time i managed miracle and given 13 cards to both NS ;D
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I wouldn't expect an alert for Gerber, at least not in 1NT - 4 !C. That was Gerber in 1950s Goren, so it seems sort of like Stayman. We don't alert 1NT - 2 !C unless it is some variant of Stayman.
Now would I try for the grand? Oh, maybe. If so, it would begin 1NT - 2 !C - 2 !D - 3 !C. A grand is a grand, no reason to fret if it is in clubs. With the actual hands we probably won't find the grand, and it's a very iffy grand if North's diamonds are AK654, perfectly consistent with the 1NT opening. Any time that a grand becomes iffy when I change a J to a 6 I don't mind missing the grand.
But suppose:
N: T8 A52 AK65 A965
S: AKQ KT98 Q8 KQ83
Now we have 3+2+3+3=11 top card tricks but if the clubs are 3-2 we get all 4 club tricks and a ruff for 13.
So trying for a grand is not crazy but with "only" a 19 count we need to find a suit fit for it to be a likely make.
Playing with my clone the auction might go 1NT - 2 !C - 2 !D - 3 !C - 3NT - 6 NT, or maybe 1NT - 2 !C - 2 !D - 3 !C - 3 !D - 6 NT
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I wouldn't expect an alert for Gerber, at least not in 1NT - 4 !C. That was Gerber in 1950s Goren, so it seems sort of like Stayman. We don't alert 1NT - 2 !C unless it is some variant of Stayman.
Now would I try for the grand? Oh, maybe. If so, it would begin 1NT - 2 !C - 2 !D - 3 !C. A grand is a grand, no reason to fret if it is in clubs. With the actual hands we probably won't find the grand, and it's a very iffy grand if North's diamonds are AK654, perfectly consistent with the 1NT opening. Any time that a grand becomes iffy when I change a J to a 6 I don't mind missing the grand.
But suppose:
N: T8 A52 AK65 A965
S: AKQ KT98 Q8 KQ83
Now we have 3+2+3+3=11 top card tricks but if the clubs are 3-2 we get all 4 club tricks and a ruff for 13.
So trying for a grand is not crazy but with "only" a 19 count we need to find a suit fit for it to be a likely make.
Playing with my clone the auction might go 1NT - 2 !C - 2 !D - 3 !C - 3NT - 6 NT, or maybe 1NT - 2 !C - 2 !D - 3 !C - 3 !D - 6 NT
Pretty much this ^^^ with all the maybes.
Although 3 !C generally promises 5+ (and by inference four of the other major) I probably trot it out in an attempt to find the grand. But I end in 6NT.
Gerber at both tables was, in my opinion, premature. The 4 !H answer to Gerber at the first was . . . puzzling. Even more so for that responder!
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I wouldn't expect an alert for Gerber, at least not in 1NT - 4 !C. That was Gerber in 1950s Goren, so it seems sort of like Stayman. We don't alert 1NT - 2 !C unless it is some variant of Stayman.
Let's not forget that in IAC we ask that all artificial bids are alerted, main reason is that we are teaching club, players and kibs learn with every hand. there is no "over"alert, pard never sees any.
Gerber happens rarely, so it wont hurt if it is alerted, and its continuations. As I understand most nowdays reply to it as 1430 where 5H= bad 2 and 5S= good 2. Seems neither table really knew for sure how to go on after darn 4C.
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I wouldn't expect an alert for Gerber, at least not in 1NT - 4 !C. That was Gerber in 1950s Goren, so it seems sort of like Stayman. We don't alert 1NT - 2 !C unless it is some variant of Stayman.
Let's not forget that in IAC we ask that all artificial bids are alerted, main reason is that we are teaching club, players and kibs learn with every hand. there is no "over"alert, pard never sees any.
Gerber happens rarely, so it wont hurt if it is alerted, and its continuations. As I understand most nowadays reply to it as 1430 where 5H= bad 2 and 5S= good 2. Seems neither table really knew for sure how to go on after darn 4C.
A line has to be drawn somewhere. If I double a 1 !S opening on my right I do not explain that it is for take-out, I don't alert a 2 !C response to 1NT. I do alert transfers including, if it is 1NT - 2 !S I explain whether it actually shows clubs or it shows one minor maybe !C, maybe !D. (I prefer that it shows clubs but I will play it either way). I probably would alert Gerber although in 1NT - 4 !C I don't know what else it would be, and if someone is not familiar with Gerber then clearly just saying Gerber would not suffice. I cannot recall this ever leading to trouble.
Unless I have discussed it with someone, I would expect standard responses, meaning that 4 !D shows no aces or four aces, 4 !H shows 1, 4 !S=2 and 4NT=3. If Charles Goren (1950s), Larry Cohen (regularly updated) and Bridge World Standard (2017) all agree (they do) that these are the responses, how wrong can it be? I recommend caution when someone tells you that they are giving you the "nowadays" responses unless they also give you references. You can trust me on Goren (I have his book), you can look up BWS
https://www.bridgeworld.com/indexphp.php?page=/pages/readingroom/bws/bwscompletesystem.html#III
and you can see Cohen at
https://www.larryco.com/bridge-articles/gerber
to see that they all recommend what I regard as the standard responses. Oh, also Richard Pavlicek
http://www.rpbridge.net/7g19.htm#73
I expect I can easily find others.
There are a lot of variations in bridge conventions and this can be a problem, but I have never had a misunderstanding with Gerber responses.
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Like Ken, I have never had an issue with my partner and a Gerber auction, with one exception. The exception is something that just does not come up often. The auction is something like 2 !C - 2 !D; 3NT - 4 !C. It is not often that you have an auction where you open 2 !C and rebid 3NT. So what is 4 !C in that auction? Most agree that it is Stayman. For many years, the ace asking convention after 3NT has been 5 !C (Super Gerber).
Where I have seen confusion has been when my partner and I have faced an unusual 4 !C bid (not part of a NT auction, but intended as ace asking). The opponents did not have the problem - they had explicitly made the agreement - my partner and I did because it was not clear that 4 !C was artificial.
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Yes, I was, for the moment, only looking at 1NT - 4 !C. For the more general situation I'll just quote from my first post on this thread:
"As with any convention, if you are going to play it you have to agree when it is on and when it is off. I play weekly, more or less, with Carl (not a BBO player). Our agreement is that 4 !C is gerber if it is a jump made directly after a natural NT bid. So: 1 !S - 2 !D - 2NT - 4 !C is a jump to 4 !C over the natural rebid of 2NT. That makes it Gerber for us. I have been playing it that way more or less forever, and most everyone I know plays it that way also."
It is certainly the case that others have different ideas as to when 4 !C is Gerber and when it isn't. In a pick-up game I would probably avoid using Gerber in the auction 1 !S - 2 !D - 2NT - 4 !C. It's true that I play that as Gerber but it does not follow that it would be understood as being Gerber if we have not discussed it. For most players, what we want is a rule that is simple and unambiguous. Must be a jump, and must be directly over a natural NT, this seems simple and unambiguous.
Of course this issue is not confined to Gerber: 1NT - 2 !D - 2 !H - 4NT? Natural with five hearts and slam invitational values, in my opinion. 1NT - 4 !D - 4 !H -4NT sets hearts as trump and asks for keys. We don't need two ways to do the same thing so 1NT - 2 !D - 2 !H - 4NT is natural. Would I be confident with a pick-up partner? No, of course not. If we have not discussed such matters, we should not be surprised when a misunderstanding occurs.
Let me be clear, at the risk of being repetitious. I am not saying that I have presented the correct way to play Gerber, I am saying that with almost all conventions there is no one expert way, no one common way, and really no one right way. So, without discussion, there is apt to be misunderstanding. I think some choices are better than others, but the really bad choice is for one person to be playing it one way and the other person to be playing it a different way.
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Hondo teaches that there are 5 situations where Gerber applies:
1 - 1NT-4C
2 - 2NT-4C
3 - 2C-2D-2NT-4C
4 - 1X-1Y-1NT-4C
5 - 1X-1Y-2NT-4C
it may not be standard but i have adopted it myself for simplicity's sake.
in the hand under discussion assuming 2D was game forcing you should jump to 4D
at your 2nd turn to set the trump suit, partner ought to show a control if he has any tolerance
for D's