Source:
Which forcing raise with a singleton do you choose? (Editor Note: We are not posting the whole article you can access to it in the link)
I asked my expert panel:
Partner opens one-of-a-major. You have a game-forcing hand with at least four-card support for partner and you have a singleton or void. With what types of hands do you splinter? With what types of hands do you make a forcing raise (Lets assume you’re playing Jacoby 2NT –meaning that a bid of 2NT over one-of-major usually shows at least four-card support for opener’s major; a game-forcing hand; and asks partner to bid a singleton at the three-level or a second good five-card suit at the four-level.) With what type of hands do you bid a suit and then support partner?
1
– 4
is a splinter. It shows at least four-card spade support, singleton or void in clubs and game-forcing values. 1
– 4
shows shortness in diamonds; and 1
– 4
shows shortness in hearts. After a 1
-opening bid, 3
shows spade shortness, 4
shows club shortness and 4
shows diamond shortness. 1
– 4
and 1
– 3
are the best splinters; they leave maximum room to explore slam possibilities.
1
– 4
and 1
– 4
are the worst splinters. There is no room to explore below game. These splinter have to be very descriptive. After 1
– 4
and 1
– 4
, there is only one bid below game. I think its best to play that the bid of the in between suit shows more than a minimum but not enough to bid above game (and says nothing about the in-between suit).
Splinters work.
You have
AKQxx
KQJx
x
xxx. You open 1
and partner bids 4
. You have at most one spade loser. If partner has two aces, you have a cold slam. Three aces and you have a grand.
The problem with bidding a suit and then supporting partner is that partner might not know that you have four-card support. After1
– 2
– 2
, there is no way to differentiate the length of your spades.
There are some experts who prefer Jacoby 2NT. Their splinters are very descriptive.
Larry Cohen: Splinter with classical hand (roughly 11 points–not more, no special feature in either side suit–not heavily weighted anywhere). Jacoby 2NT on other hands, unless I have a good reason to show a side suit and hear a reaction.
Jill Meyers: I splinter with hands where I have controls in the other two suits; and not with a hand where I have a good five card suit to bid at two level. If I didn’t have a good five-card suit and I didn’t have controls in the two unbid suits, I would bid Jacoby 2NT.
Ralph Katz: Splinter with about 12-14 HCPs. I also don’t have a side holding of Jxxx or worse. I use Jacoby 2NT with probably all other hands that don’t qualify for a splinter. You probably should also use Jacoby 2NT with a side suit of Jxxx or worse; not only would it be great to find partner with a singleton in that suit, but when they don’t have that singleton why help the opening leader.
You also probably should Jacoby also with a side suit of Axx and certainly Axxx. I probably would never start with a two-level bid. That’s because an opening bidder with AQx in the two-level suit bid by responder will think they are at least five tricks for us in that suit. A two-level response also helps the opponents too much. Maybe if you as a responder were in a bidding contest, you would make your first bid suit at the two-level way.
Henry Bethe: My agreements are: A direct splinter shows either a minimum game force or a hand worth a drive to the five-level. I treat “seven loser” hands as a minimum GF, e.g.

Kxxx

Axxx

x

Kxxx would be about average for 1

– 4

. With

Kxxx

AQxx

x

AQxx I would splinter and bid again over 4

. With a hand in between I go through 2NT. The hands on which I bid a new suit, then force to game have a source of tricks, e.g.

Kxxx

xxx

x

AKJxx I would start with 2

.
Other experts prefer the splinter.
Kit Woolsey: On most hands I would splinter. I might bid Jacoby 2NT if my other side suits were something like Axxx and KQxx. Now catching a singleton in the right side suit would be gold. I guess I could bid a side suit first if everything appears to depend on the fit for that side suit — something like

Qxxx

x

AQ10xx

AKx. But I don’t think I have ever done that — good rule of thumb is to set trumps as quickly as possible.
I should add that my answer assumes I am playing Standard American with normal Jacoby. If I am playing Precision I am much more likely to bid Jacoby, since with partner’s hand being limited I am better placed to make the full decision — particularly if the Jacoby structure is sophisticated.
Bob Hamman: My opinion is that bidding over splinters is quite sensitive to context. Therefore I prefer to either incorporate splinters within the 2NT response or have some other bid which allows opener to somewhat define his strength, such as one-under limit raises. With respect to bidding suits and then raising, I recommend a method such as one-of-a-major-2NT = GF raise + side suit and one-of-a-major-3

is a balanced raise or moderate splinter. 1

-3

or1

-3

is a limit raise or game-forcing splinter with accepts being made by bid of one-over-trump-suit.
Eddie Kantar:” I don’t respond 2NT with a singleton; against my religion. If I’m that strong, I splinter. If I have 10-12 HCP, I jump to 3NT, partner asks with 4

. If I have 13 or more I jump to three-of-the-other-major and the next step asks. With weaker hand I either make a limit raise (3

), or a preemptive raise (3

). I can’t imagine raising to the two-level with four trumps and a singleton, though I guess there are some hands that qualify. I might also jump shift (don’t play many strong jump shifts – just from one of a suit to 2

) and then bid my singleton as the jump shift either shows a one suited hand or support for partner. Bidding a new suit shows a singleton, presumably with a hand that has support.
Experts suggest their conventions.
Barry Rigal: As to what I think you SHOULD do: Use two-tier splinters (1

-3

and 1

-3

for 9-12 splinters), with 4

/4

/4

as 13-16 splinters. Given that you don’t do this — and in fact even if you do — you should not splinter directly with a five-card suit (particularly a minor) with KJ10xx or better. The source of tricks may be critical to slam making. Bid the suit then splinter.

AKxxx

KQx

Qxx

xx facing

QJxx

x

AKx

Axxxx has 11 tricks and no chance of more.

AKxxx

KQx

Qxx

xx facing

QJxx

x

AKxxx

Axx probably makes 12 tricks in a canter unless both spades and diamonds do not split. With a stiff ace or especially king splintering is very dangerous, whether minimum or maximum for the planned auction. 2NT may be better. Don’t splinter with a void if 13+ (with 9-12 it may be the least harmful lie). 2NT then unusual jump for exclusion, with a void.
Rigal suggests two-tier splinters. 1
-3
shows 9-12 HCP, four-card support with an outside singleton. Over 3
, 3NT asks for the singleton. Then 4
, 4
, 4
t show singleton club, diamond, spade. If you have a minimum opener, you don’t have to ask for responder’s shortness. He suggests 1
– 3
as a spade splinter but I like 1
– 3NT as a 9-12 splinter. Over the splinter, next higher bid asks for shortness. Using two-tier splinters, all other splinters show at least 13 HCP, usually 13-15. 1
– 3NT shows a 13-15 spade splinter. All other splinters are natural.
The following experts use limited splinters.
Curtis Cheek; I splinter on 90% of hands with 11-13 HCP (hedging my bets – probably 95+). I make a forcing raise with 95% of hands with 15+ HCP. 14 HCP is the breakpoint. I just try to put them on one side of the line or the other. I bid a suit with about 13 HCP with xxx in a side suit. In reality I hardly ever (the remaining 5% at best) bid like that with four-card support. I like partner to ‘know’ I only have three-card support to aid in his evaluation of the trump situation.
Marty Bergen : I splinter on all hands with fewer than 17 points, counting distribution and bid Jacoby 2NT on stronger hands. I never bid another suit.
Richard Freeman: I splinter with no outside five-card suit unless weak, bid 2NT with very strong trumps and bid a five or six-card suit with two of the top three honors.”
Nick Nickell: Splinter should be used with hands that fall into fairly tight ranges. Dick Freeman and I utilize three-of-the-other-major as showing four+ trumps, an undisclosed splinter and 9 -12 HCP. Opener can ask to find out partner’s singleton or just place the contract and leave the opponents in the dark. We splinter at the four-level to show 13 – 15 HCP with 4+ trumps. We do not splinter with better hands, or hands that seem better suited to asking about partner’s hand type.
We tend to bid a new suit and raise partner when you have a concentration of honors in our suit and partner’s suit without any side controls.

AQxx

xx

xx

AQxxx is a hand where we would bid 2

over 1

and then bid 4

. With most other hands we start with a forcing raise.
I like a jump to game in this situation to show a very bad two-over-one. Shows no outside aces with at most one trump honor. An example would be ªQxx
QJx
KJx
KJxx.
Jeff Rubens: I splinter with a game-force with side shortness seeming most important. I make a forcing raise with neither side shortness nor useful-looking side suit. I bid a suit when the side suit looking most important.
Bobby Wolff: When playing Jacoby 2NT I prefer to only splinter with classic type hands, e g. 4

over 1ª with ªAJxx

K10xx

x

Axxx. 11-13 HCP, usually four but very occasionally five little trumps; a singleton not a diamond void. With all others I would go through 2NT and ask and then perhaps tell when asking partner to help with the decision. Some hands where I would change suit at the two-level and then either raise or jump raise partner’s major are: Over 1ª: ªKxxx

xx

AKJxx

Kx bid 2

and then over 2ª or 2NT I rebid 4ª; with ªKJxx

AKQxx

xxx

x over 1ª bid 2

then over either 2ª or 2NT, I splinter with 4

. With ªAQx(x)

xx(x)

AKQJx

xx I would jump shift to 3

and then raise spades. My tendency is for the responder to underbid slightly giving the opener some leeway (perhaps at times too much) with his opening bids.
Chip Martel: Complicated answer since it depends on several factors: hand strength (the stronger the more likely to bid 2NT), honor location (with pure holdings, helpful to find out about partner’s shape), space considerations (4

over 1

leaves no space, 3ª over 1

leaves a lot). For the last question, with four-card support only show side suit if good but not solid (ideally AQxxxx) or so solid it might be the trump suit. I give responder the option to show a strong splinter after bidding 2NT. (Opener bids 3

with all minimums
and 3

with no stiff and extras. Over these, 3ª and four-of-a-minor show a splinter with 15 –17 HCP.