smerriman

Agreed. Am in the context of this being a robot tournament.

Everyone will open 2NT. And every North in the field is guaranteed to bid minor suit Stayman. I can't think of any sequence from there that won't end in slam.

That's not correct. When small slam is certain, a vulnerable minor suit grand needs to be 55% to make it profitable at IMPs (13 IMP gain vs 16 IMP loss). It would go up to your 68% if you thought three quarters of the field would be in just game, but surely everyone will be in at least 6 here.

The primary meaning of double is "I want to play in your best suit". It does not mean "I have an opening hand". A lot of people new to the game double with shortness in another suit, find partner bids that suit, and then try to escape by bidding something else. This does not work. In fact, by saying "I want to play in your best suit", and then on the next bid saying "Actually, I don't", you are showing a very strong hand, too strong to simply overcall the first time. If you have a hand not suitable for a double or overcall, you have an easy bid - it's called pass! Again, contrary to what people new to the game think, this does *not* deny an opening hand. If the LHO bids on, you will get another chance to bid and more accurately show your hand. If the LHO does not bid, the meanings of your partners bids change in order to 'protect' you. For example, if they are short in the opener's suit, they should almost always double - even if quite weak - hoping you will pass and collect a large penalty.

Even GIB, one of the worst bidders in competition, finds 6♦ with and without the 2♥ interference.

GIB bids very poorly when it comes to slam auctions. It doesn't understand the principles of cuebidding (as you can see 4♠ is defined as 26+ total points which is literally impossible) or what high level bids mean. Here you need a way of telling if partner has the diamond queen. I'll leave it up to somebody else for how expert humans would handle this, since I don't know. But I can tell you it is impossible to find out with GIB. If you're solely looking to improve your scores with GIB, you're often better off bidding badly / lying about your hand in order to take control of the auction (ie, bid 4NT yourself instead of 4S, hear partner has two aces, then take a wild guess what to play). This is why bidding with GIB can hurt your game in general - but it's still fun to learn how to outwit the robot. PS - the probability of making grand slam with your hand and dummy is 52%. This means if you're playing matchpoints, 7♣ (well, I guess 7NT) is the correct contract, even though it goes down on this layout - but you don't want to be in it if playing IMPs, which needs to be at least 55%. Edit - good point, Cyberyeti. It's 57.9%. Maybe minus a tiny bit for a ruff in another suit. So in fact, grand slam might be the right spot on these hands. Just not the right way to get there.

2♠ on that hand looks far better than 2♥ on the original though - it's more preemptive than hearts, you have an Ace, and the ability to ruff clubs.

PS - if you hadn't seen this already, GIB also only jump shifts on very specific hand types, not all 17 point hands - see the description here: https://www.bridgebase.com/doc/gib_system_notes.php#soloway_jump_shift

Well, you actually did, but I'm guessing now it was more of a typo and you meant to say 'non-game-forcing', which changes things a little :) Going back to your example, suppose you hold AQJxx-x-Kxx-Jxxx, and the auction goes 1♦ - 1♠ - 1NT. You now need to know two things - whether partner is minimum (want to play a partscore, not game), and whether partner has three spades (want to play spades, not no trumps). 2♣, new minor forcing, gives you precisely the answers to these two questions. You will know immediately what the final contract should be. Give yourself an extra spade: AQJxxx-x-Kxx-Jxx Now you know you want to play in spades, and need to know whether it should be in game or not. Bid 3♠, telling partner to pass with a minimum or bid game otherwise. Make your original hand a little stronger: AQJxx-x-Kxx-Axxx Opposite a 1NT rebid, you know you want to play game and not slam, but don't know whether it should be spades or no trumps. Again, after new minor forcing, you will know exactly the right contract. With these hands, perhaps opener will bid something other than 1NT. Now you can use other sequences to continue in different ways. If you decide to jump shift instead, you'll quickly find yourself stuck - you don't know whether opener has a minimum, medium, or maximum hand; opener doesn't know whether you have 13 points or something much stronger; and neither of you know what suit you want to play it. You can communicate some of this information, but not all of it in time. That's why Soloway jump shifts are restricted to certain hand types (and have nothing to do with points - that's just GIBberish - there are plenty of 20 point hands you shouldn't jump shift with, and some weaker ones you should) - ones where the information you need to know can be communicated in time. The main point is that standard bidding covers most sequences pretty well - not every single one, but again, each time you come up with a hand you think the system doesn't handle well, send it through and you may find there is actually a good solution. (Not necessarily one that works with GIB though :() In fact, I don't recall the last time I made a strong jump shift. If you're getting started with 2/1, I'd suggest not using them at all - once you're more familiar with how all of the alternate options works, you'll start to learn if/when they're needed. (Most people on BBO would assume a jump shift is weak too.)

You said you don't like the fact you can't bid 1♠ because it's not forcing.. which explained why you thought you had to jump shift.. I have no idea how pointing out 1♠ is forcing is a straw man argument. Still yet to see any limitations of 2/1 in this thread, but I give up for now, since it seems any attempts to help are being misinterpreted as attacks. Once you realise people are only trying to help, please keep asking questions - it's the best way to learn.

If you thought 1♠ was non-forcing that's a pretty major issue - the entire system would be unplayable if that were the case! But hopefully having that cleared up will make all of the other bids discussed make a lot more sense.

1♠ is 100% forcing, whether you are playing 2/1 or not (unless you are a passed hand - and even then opener will only be passing in very very rare situations where 1♠ is likely to be the best contract). 1NT is not forcing over a minor opening; it shows a weak hand and no 4 card major. I'm not sure which auction you're referring to here - eg if partner opened a minor, you won't be missing a major fit since you would have bid the major. But it sounds like you may have misunderstood what 1M shows. Thinking 1♠ is not forcing may well explain everything else in this thread! (And that was the purpose of prior replies - figuring out where your misunderstanding was - so please don't get put off posting by anything :))

I think the biggest thing you need to think about is - why do you *want* to jump shift? If you bid 1♠, whatever partner responds, you have low-level forcing continuations (NMF et all over 1NT, third suit forcing over 2♦, fourth suit forcing over 2♣, and so on) if you decide you don't want to sign off in game. If you jump shift, your next bid is going to be at the three level. You're not going to learn as much about opener's hand, and you're going to have a lot less time to find the optimal contract - which is why people only use them in very specific situations that can't be described well by starting with 1♠. This current hand can be described well in all cases by starting with 1♠. Note there are also some strong hands with 17+ points where you still don't want to jump shift - because it's more important to have the extra room to bid.

PS - I found the hand you posted. Nobody else bid slam. If you get to 6♠, the robot will lead a heart and you'll go down - losing over 10 IMPs to the field.

I really don't understand this at all. a) The hand you posted isn't anything to do with 2/1. It would be bid exactly the same if 2/1 responses weren't forcing to game. b) What do you think the limitations of the system are in the examples you posted? As mentioned, you can easily explore for slam on the first hand by bidding 2♣, or whatever choice of forcing bid you have at the two level. 4♠ says "I want to play 4♠, and I don't want to play slam". I don't see any limitations of the system there. Also as mentioned, there are no point restrictions on Soloway jump shifts, so there are no limitations there. 2/1 just makes these sequences easier, since you can force to game without having to jump shift - allowing the jump shift to be much more descriptive. c) A good bidding system should avoid slams where good opponents can cash the first two tricks. If you disagree with that.. then I guess just bid Blackwood and hope. But giving you ways to avoid this isn't a limitation of the system.

.. you're losing the first two tricks in hearts. If there's a system which gets you to slam, I'd suggest avoiding it :) If playing new minor forcing like GIB does, and you had a hand with 6 spades where you wanted to investigate slam, you can start with 2♣, then rebid your spades. That sets spades at a lower level than 4♠ (which is a signoff here). That would theoretically allow you to start cuebidding, notice the heart issue, and stop. GIB doesn't understand cuebidding so this probably wouldn't work, but that's an issue with GIB, not 2/1. With a human it's probably even better to play two way checkback, which makes things even easier. (But for your hand, I don't think you want to be looking for slam. Your partner has the absolute best possible hand he can have, and slam is still no hope). There are no point restrictions on Soloway jump shifts. (Yes, GIB mentions a point range, but it assigns all sorts of arbitrary points ranges; you don't need to obey them and sometimes they make no sense). However, you should only be using them on very tightly defined hands; since you can already force to game with a 2/1 you need a good reason to waste a lot of bidding room. Hands suitable for a jump shift are very rare (which is why many people don't play them).

Every system has limitations. 2/1 makes some sequences far simpler, at the cost of making others more difficult. The same applies to lots of conventions regardless of the underlying system. In saying that, firstly GIB has many many many issues with it; so the fact it gets things wrong doesn't necessarily mean that is an issue with 2/1. Secondly, you really need to come up with a specific list of sequences you are having difficulty with, since you may well simply be misunderstanding how they work in 2/1.

Sorry, but that one is entirely your fault. Playing Soloway jump shifts, as GIB does, your 4♣ bid shows support for hearts and shortness in clubs. Your further diamond bids are then clearly cuebids.

In the forum daylong, *everyone* plays the same hands. So might want to wait until it's over ;)

Those stats don't make any sense. The opposition are guaranteed enough points for game. Virtually the only time that you will be playing 2♥x is when your LHO has at least 5 hearts and your RHO is short, reopening with a double. I ran a sim of 500 hands that meet those conditions: Down 3: 9/500 Down 4: 85/500 Down 5: 230/500 Down 6: 149/500 Down 7: 27/500 So you are guaranteed to score worse than the opposition's game; and almost certainly worse than the opposition's slam (if they even have one). Even if I relax the condition to LHO only having >= 4 hearts, you're still far worse off to whatever the opposition would have bid to. So if you find yourself in 2♥x, you will be losing a lot of IMPs. Another case where you may lose IMPs is when you find yourself in 4♥x or 5♥x when partner sacrifices. This is never going to be a good result. So in order to gain, your opposition must bid over 2♥ and not find the right spot. And this has to be a large gain to counter all of the IMPs losses from playing in hearts. "Given the level of interference this causes", can you name a single hand where 2♥ prevents the opposition from finding their optimal contract? Let alone enough to make up for the above..

I did a quick sim myself, and got similar results to johnu (diamonds being the worst at both MPs and IMPs). Hearts came out slightly ahead of the other two choices for both scoring formats. Though again, that's double dummy, so doesn't necessarily prove anything.

Right - in that case you'd need to include a lot of hands without a fit in the 2♣ bid. GIB plays 2♣ as showing spades, so 3♥ shows a good hand with hearts but denies spades.

What are you suggesting should change? - 2♥ forcing? This may be playable but definitely not standard - you want to be able to bid a non-forcing 2♥ just to improve the contract (say, with a decent 6 hearts and a spade singleton/void, but not much else). - jump to 3♥? If you then have, say, 2 hearts, you aren't going to have much choice but to raise hearts and lose the preferred spade fit. The cost of either of these seems to outweigh the tiny amount of time when you don't want to play in the known spade fit. If you have enough for slam, you'll know it because opener won't bid 2♠. This isn't really anything to do with GIB's system - the definition and bid of 2♣ seem very standard. (You can play that 2♣ doesn't guarantee support, but you'd still bid it here anyway.)

That.. is inexcusable.

What is weak about it? 2♣ is the only possible bid here. A new suit in response to an overcall is not forcing, so you definitely don't want to be bidding 2♥, especially when you know you have a spade fit. There are different ways to play jump shifts by advancer; GIB plays 3♥ as forcing, but denies spade support. So don't want to be bidding that. 2♣ is forcing, but nothing to do with seeking slam; it just shows good support and asks for more information about your hand. You show your minimum with 2♠ (2♥ would show a better overcall); partner can choose whether to pass, make a game try, bid game, or more. Here there's nothing more to do than bid game.