Splinter bids are bids that (by agreement) show shortness. There are a large number of possible bidding sequences where a splinter can usefully be defined. Some are commonly known and used, others are less common and typically only used by regular partnerships. In general, it pays to take a little time to define a fairly wide variety of splinters, and use them as often as possible, for a couple of reasons. First, the overhead cost is low: the bids defined to be splinters typically have no other particularly good meaning, and the memory-burden is generally small (for that reason). Second, the payoff can be quite large. Knowledge of a singleton or void in partner’s hand allows a much more focused assessment of your values, which can lead to games and slams on relatively low point-count when assets are working, and also to good stops when combined high point-counts are not fitting so well.
All splinters are alertable, whether or not most people play them.
1) The splinter bids that everyone knows are 4-level responses to a major-suit opening. For example, 1H – 4D! shows a game-raise of hearts that includes a singleton diamond. To give this better definition, we should note that this sort of raise is laying some groundwork for slam bidding, so the raise to game needs to be full-strength: 10+hcp, no more than 7 losers on the LTC, and including 4-card trump support. That doesn’t make it excessively strong, and with many hands, opener will merely return to game and that will be the end of the auction. But even with a near-minimum, opener may want to investigate if it looks like the hands fit well. The Losing Trick Count is a better guide, but a rule for high card points is that slam will usually be a good bet if you can count 27 points in the combined hands counting only the ace in the splinter suit, or with 24 points and no high cards in the splinter suit. (This rule guarantees that you will not be off two cashable aces or the ace and king of a suit.) The one sequence I always mention to a new partner is 1S – 4H. I like to play that as a splinter raise of spades, some people like to play it as natural. I can live with it either way (for one session), but I really hate playing 4H in a 3-1 “fit”.
2) A similar sort of splinter happens the other way round, in sequences that begin 1minor – 1major. For example, in the sequence
1C – 1H; 4D!
opener is showing a game-raise of hearts that includes a singleton diamond. Typically, opener’s hand will not only be in the upper range (16+hcp) but will also include length in his first-bid suit. Responder should be aware of the possibility of a double-fit, if he has some support. A special case is sometimes called an auto-splinter: this where opener “splinters” in his own suit, for example
1C – 1H; 4C!
This sort of sequence should show a solid 6-card suit, 4-card support for responder, and an unspecified singleton in one of the other two suits.
3) Some bids of a new suit at the 3-level can also be defined as splinters, similar to those just mentioned but forcing only to 3 of responder’s major. For example,
1C – 1H; 3D!
doesn’t have an obvious natural meaning, since 2D would be a reverse and so opener doesn’t need to jump to show strength. I recommend that this and similar sequences be played as splinters supporting the major. Some attention has to be paid, since some sequences are needed for natural bidding, for example 1D – 1H; 3C looks similar, superficially, but opener is just showing clubs and a good hand. I don’t think there is much real risk of a misunderstanding, because the general rule is that if a bid might be natural, it is. It’s only the “jump reverses” and other such oddities that become splinters.
4) Any unusual jumps (often a jump in a sequence that is already forcing) should probably be treated as a splinter. For instance, playing inverted minors,
1C – 2C; 3H!
should be a splinter where opener is 16+ and is suggesting game or slam in clubs, and alerting responder to only try 3NT if he has the hearts well-covered.
1NT – 2D; 2H – 4C!
should imply a 6-card heart suit and be a mild slam try, since just bidding 3C would show a club suit and be forcing. This rule of thumb can be applied in competitive auctions, also, although I’m sure some partnership discussion is needed. But whether you are the opening side or the overcalling side, there are a lot of sequences where a jump or double-jump in a new suit makes no sense normally and can be used as a splinter raise of partner.
5) Splinters typically show singletons. They can also show voids, which can cause problems. A solution for the 1major – 4x type of splinter (paragraph 1) is to set aside the cheapest triple-jump bid as a void splinter, showing a void in an unspecified suit. The 3NT response (currently unused) comes into play for this. So
1H – 3S and 1S – 3NT
are the void splinters. Opener bids the next step as a relay for responder to show where the void is (bidding 4 of the trump suit to show the suit that isn’t available to bid below game level):
1H – 3S; 3NT – 4C/D/H void in clubs, diamonds or spades respectively
1S – 3NT; 4C – 4D/H/S void in diamonds, hearts or clubs respectively
The only singleton splinter that is compromised by this scheme is 1H – 3S. That is fixed by using 1H – 3NT as (specifically) a splinter showing a singleton spade.
This idea has a little bit more memory-burden than basic splinters, but it does clear up an (admittedly rare) issue using only otherwise-unused bids.
I play all of this stuff with Elwood. Agent 99 wouldn't go for the void splinters, but Elwood has a mischievous streak.
