Bidding and conventions
Splinter bids
Partner opens 1♠. You hold four spades, 13 points and a singleton club. Whether that is a game or a slam depends entirely on which cards partner has wasted opposite your shortage, and a splinter is how you ask.
Why shortage is the fact worth showing
Opener holds a normal 14-count with five spades. Responder splinters 4♣, showing spade support and a club singleton. Watch what that does to two almost identical opening hands.
14 points, none of them in clubs. Every honour is pulling its weight opposite the shortage.
The same 14 points, but the club king and queen are opposite a singleton and take no tricks at all.
Same suit, same length, same point count, and the difference between a slam and a part-score's worth of extra tricks.
No amount of counting points separates those two hands, and no convention trading in strength alone can either. The splinter asks the only question that distinguishes them.
What you need to splinter
- Four or more cards in partner's suit. Not three.
- Game-forcing strength — roughly 13 to 16 support points. Enough to insist on game and not so much that you have a stronger route available.
- A singleton or a void in the suit you bid, and nowhere else.
13 points, four-card support, a club singleton, and nothing else unusual to say.
How opener answers
Opener now re-values, and the question is entirely about the splinter suit:
- Wasted values there — ♣ K Q x opposite a singleton, ♦ Q J tight opposite a void — sign off in four of the major. Those honours are worth nothing and the hand is worse than its point count.
- Nothing wasted — small cards opposite the shortage, and the rest of your strength in the other suits — cue-bid an ace and get the slam auction going.
- An ace opposite the shortage is neither: it is not wasted, because it was always a trick, but it is not working either. Treat it as a normal card and judge on the rest.
| West | North | East | South |
|---|---|---|---|
| 1♠ | |||
| Pass | 4♣ | Pass | 4♥ |
| Pass | 4NT | Pass | 5♠ |
| Pass | 6♠ | Pass | Pass |
| Pass |
Voids, and why they are awkward
A splinter shows a singleton or a void and partner cannot tell which. Usually that is fine — both make partner's honours in that suit suspect, but a void is worth substantially more.
The common refinement: a jump to the five level shows a void, leaving the four-level jump as a singleton. It costs nothing and it is one more thing to remember. Most pairs do without it.
Opener can splinter too
The convention is not responder's alone. After 1♦ — 1♠, a jump to 4♣ or 4♥ by opener is a splinter agreeing spades: four-card support, shortage in the suit bid, and a hand too good for a simple game raise.
It is rarer — opener more often has a second suit worth bidding naturally, but the logic is identical and it wins the same slams.
What it costs
The natural meaning of a double jump in a new suit, which was almost nothing. A hand wanting to play in 4♣ opposite a 1♠ opening is close to non-existent, and any hand with real clubs and real values has a slower route available.
The genuine cost is different: a splinter tells the opponents where your shortage is. The defender on lead now knows what not to lead, and often what to lead instead.
On hands where you stop in game anyway, that is a free gift. Worth making regardless — the slams found are worth more than the part-scores defended slightly better.