[Knurdler]

Sorry for confusing everything.
My post appeared so bad I deleted it.
But while I was editing, Smerriman has copied a reasonable looking table and replied.
I compiled the table from various sources, a lot from Larry Cohen.

Most of the table makes sense to me but some bids could not find such has jump shift and splinter after 1H 1S. They cannot both be 4C and 4D.
I mostly play SAYC. I do not play 2 over 1 as a system.

[smerriman]

Knurdler, on 2024-January-27, 13:49, said:

First	Reverse	Jump shift  Splinter	Mini
2 bids          Shift                   Splinter
                          
1♣ 1♦	Na	2♥ 2♠	    3♥ 3♠	Na	
1♣ 1♥	2♦	2♠	    4♦ 3♠ 	3♦	
1♣ 1♠	2♦2♥	Na	    4♦ 4♥ 	3♦ 3♥	
1♣ 1NT	2♦2♥2♠	Na	    Na	        Na	
1♦ 1♥	Na	3♣ 2♠ 	    4♣ 3♠ 	?♣	
1♦ 1♠	2♥	3♣	    4♣ 4♥ 	?♣ 3♥ 	
1♦ 2♣	Na	3♥ 3♠	    4♥ 4♠	Na
1♦ 1NT	2♥ 2♠	Na	    Na	        Na	
1♥ 1♠	Na	3♣ 3♦	    4♣ 4♦	?♣ ?♦	
1♥ 2♣	Na	3♦ 3♠	    4♦ 4♠	Na
1♥ 2♦	Na	3♣ 3♠ 	    4♣ 4♠ 	?♣
1♥ 1NT	2♠	Na	    Na	        Na	
1♠ 2♣	Na	3♦ 3♥	    4♦ 4♥	Na	
1♠ 2♦	Na	4♣ 3♥	    ?♣ 4♥	?♣	
1♠ 2♥	Na	4♣? 4♦?	    4♣? 4♦?	?♣ ?♦

This depends on whether you're playing 2/1 as game forcing or not. If so, there is no need to ever jump after a 2/1 to show a strong hand, so the strong jump shift column doesn't exist for those cases and those bids turn into splinters instead.

[jillybean]

https://www.bridgeba...everse-bidding/


Great topic. I know it is not at all helpful however I would recommend you start playing 2/1 as soon as you can.
I found it a lot easier to bid these strong hands in 2/1 where in SAYC I was trying to jump shift, reverse or splinter.

[smerriman]

Knurdler, on 2024-January-27, 13:49, said:

Most of the table makes sense to me but some bids could not find such has jump shift and splinter after 1H 1S. They cannot both be 4C and 4D.
I mostly play SAYC. I do not play 2 over 1 as a system.

Your table had the correct jump shifts after 1♥ - 1♠ (namely, 3♣ and 3♦).

Rather than a big table, it's easier to think about the logic of the bids.

If you're bidding a new suit that ranks lower than your original suit, then the cheapest level is the natural / weakest version. You thus need to jump one level higher with very strong hands to ensure partner doesn't pass. Jumping two levels is a splinter.

If you're bidding a new suit that ranks higher than your original suit, even the cheapest level has to show a stronger hand since partner has to go a whole level higher to correct back to your first suit. That's considered a reverse and is therefore forcing. Since it's forcing, you don't need to jump to force, so any jump is a splinter. If you have two possible jumps below game, then one can be a mini-splinter.

[Knurdler]

I agree that logic is the way to go. Thanks Smerriman.

As I explore this topic, I find further areas of ignorance.
1. Is 1D 1H 1S forcing?
2. Assuming 1D 1H 1S is not forcing; is 1D 1H 2S a reverse (17+ points) or a jump shift (19+ points)?
3. If a splinter and mini splinter are both possible, such as 1D 1H 4S or 1D 1H 3S. How do I choose which one to bid?

[DavidKok]

I'll answer your questions twice - once with what (I believe) is standard, once with what I prefer to play.

Standard/common/I'm sure somebody will correct me that their local standard is different:

• 1♦-1♥; 1♠ is not forcing, and limited to approximately a bad 17. Responder will usually keep the bidding open but may pass with a bust, i.e. a sub-responsive hand that just wanted to get out of diamonds. Experts will usually respond to 1♦ with a hand like ♠xxx, ♥QJTxx, ♦x, ♣Jxxx planning to pass this 1♠ bid.
  
• I think you've gotten the terminology confused. This bid is a jump shift, in that we are making a jump bid in a new suit. However, it also shows approximately 18+ (may upgrade nice 17's). It is forcing, and some partnerships play this as forcing to game.
  
• This is a poorly chosen example, as 3♠ (splinter for hearts) already commits to game. Generally a mini-splinter is a raise to only 3-of-the-trump-suit, showing shortness along the way. By contrast a splinter forces us to the 4-level and shows a stronger hand. Mini-splinters opposite a simple response show approximately 13-15 HCP (so that with the singleton they evaluate to a jump raise to 3M) while full splinters in this case show approximately 16+ HCP. In standard systems mini-splinters are quite rare - the only auctions that meet this condition are 1♣-1♥; 3♦, 1♣-1♠; 3♦, 1♣-1♠; 3♥ and 1♦-1♠; 3♥, and even then not only is it wise to discuss these bids before employing them as they aren't completely standard, also you may wish to use these bids in other ways instead(?).

My personal preferences are:

• I prefer for this sequence to be not forcing but more wide ranging. I'll take my chances of missing game with misfitting 5-6 facing 18-19 at the 1-level. Between Dutch Doubleton and Unbalanced Diamond the problem is almost entirely eliminated, but even in standard systems I never liked the approach to opener's major suit jump rebids.
  
• In my opinion the standard way to handle these jump rebids is silly. By splitting it approximately 11-17 versus 18+ we guarantee getting to game when responder 'only' has 6-7. However, 7+ HCP is considered a full response these days, and opener will almost always take another bid if we just bid our major at the 1-level (be it a lawful raise, a 1NT or 2m pull, or even some XYZ gadget). The case where the jump shift wins is where responder would have passed a 1-level response but game is on anyway. This is an extremely narrow target - no 4-card support for our major, not enough strength to take another bid, but game has to be on anyway. I reckon this takes 20+ rather than 17+ almost always. By contrast the losses from jumping are significant - we're behind on setting trumps and investigating choice of game or slam, we're forcing to the 3-level facing a possible sub-minimum response, and we've just nuked all our XYZ/NMF/Checkback gadgets. Personally I'd much rather reserve these jump shifts for very strong (20+ or so) hands, or, even better, reserve them for artificial raises of partner's major suit. The costs of simply rebidding 1M on some 18- or 19-counts are very slim.
  
• In general I prefer for splinters to be highly specific hands. We are taking away most of our bidding space on a possible slam auction, so partner should be in a great position to decide what to do after to justify eating up all their space. Again Dutch Doubleton and Unbalanced Diamond come into play here, but more generally my requirements for the types of hands are a bit stricter than most.

[pescetom]

DavidKok, on 2024-February-02, 03:07, said:

My personal preferences are:

• I prefer for this sequence to be not forcing but more wide ranging. I'll take my chances of missing game with misfitting 5-6 facing 18-19 at the 1-level. Between Dutch Doubleton and Unbalanced Diamond the problem is almost entirely eliminated, but even in standard systems I never liked the approach to opener's major suit jump rebids.
  
• In my opinion the standard way to handle these jump rebids is silly. By splitting it approximately 11-17 versus 18+ we guarantee getting to game when responder 'only' has 6-7. However, 7+ HCP is considered a full response these days, and opener will almost always take another bid if we just bid our major at the 1-level (be it a lawful raise, a 1NT or 2m pull, or even some XYZ gadget). The case where the jump shift wins is where responder would have passed a 1-level response but game is on anyway. This is an extremely narrow target - no 4-card support for our major, not enough strength to take another bid, but game has to be on anyway. I reckon this takes 20+ rather than 17+ almost always. By contrast the losses from jumping are significant - we're behind on setting trumps and investigating choice of game or slam, we're forcing to the 3-level facing a possible sub-minimum response, and we've just nuked all our XYZ/NMF/Checkback gadgets. Personally I'd much rather reserve these jump shifts for very strong (20+ or so) hands, or, even better, reserve them for artificial raises of partner's major suit. The costs of simply rebidding 1M on some 18- or 19-counts are very slim.
  
• In general I prefer for splinters to be highly specific hands. We are taking away most of our bidding space on a possible slam auction, so partner should be in a great position to decide what to do after to justify eating up all their space. Again Dutch Doubleton and Unbalanced Diamond come into play here, but more generally my requirements for the types of hands are a bit stricter than most.

My personal preferences for 1 and 2 coincide with yours, basically because it increases the frequency of XYZ which is so productive. This is only explicitly agreed with the best partner though (who was clearly stretching to rebid at 1 level anyway).
As for 3, I have experimented with various schemes for dual splinters in the past and come to the conclusion that they do not pull their weight. I prefer to just agree that the 'mini' splinter is the only splinter, keeping things simple and not eroding the space for control-bidding.