Get The Tweezers!

♠ 4 ♥ Q 8 4 3 ♦ A J 10 8 ♣ A 8 7 2
Nobody vulnerable, partner opens 1 ♥. Your call?

ANSWER: Bid 3 ♠, showing at least 4-card heart support, game-going values, and a singleton or void in spades.

THE PRINCIPLE: An unnecessarily high jump to a new suit is called a splinter. It shows game-going values in support of partner's last suit, and a singleton or void (a "splinter") in the suit named. It suggests slam interest, in that your hand can ruff partner's losers in that suit. Note that a splinter bid must be Alerted.

A 1 ♠ bid from your hand would have been natural for spades. A 2 ♠ bid would have shown spades, and the meaning would depend on your partnership agreements. In the old days, the jump shift response promised a very strong (17+ HCP) with a good suit. Many partnerships nowadays play the jump shift as weak; there are other possible conventional treatments.

But the unnecessary jump shift – in this case, a double jump shift – is Standard American bridge-speak for "I am short in this suit, and have at least four-card support for your suit. Does that pique your interest in slam, partner?"

Partner can then consider whether your ability to ruff that suit is good news (covering some losers) or bad news (if she has wasted values in that suit). If partner holds something like
♠ J 8 3 ♥ A K J 10 6 ♦ K Q 6 2 ♣ 4
she will realize that the partnership holds first- or second-round control of every suit. No longer worried about too many spade losers, she can bid 4 NT Blackwood, asking for aces. You would show two aces, and partner can bid the easy 25 HCP slam!

Opener can show a splinter, too; not just responder.
♠ A 6 3 2 ♥ A Q 5 2 ♦ A K 10 8 3 ♣ --
You open 1 ♦, partner responds 1 ♥. Of course you want to be in game at the very least. Bid 4 ♣, showing game-going values with four-card heart support and a singleton or void in clubs. Partner will Alert and can take it from there...

The splinter bid sets the trump suit and commits the partnership to game. Any subsequent bids other than in trump are then cue-bids showing controls in whatever style your partnership uses. And if the opponents wander into our auction, forcing passes are in effect; you will either bid one more or double the opponents.

After a splinter bid, partner is in charge of the auction because you (presumably) have fully described your hand. Consequently, splinters by responder are usually limited to at most 14 HCP or so. If you do have significant extra values, better not to splinter; take charge of the auction yourself such as through a Jacoby 2NT game-forcing raise.

BONUS MINUTE: The splinter bids described above are double jumps, but splinters can be used in other situations that are only a single jump. When playing 2/1 Game Force a two-over-one bid by responder creates a game-forcing auction, so there is no need for opener to make a jump shift rebid to force to game. After a game force has been established, a jump shift into a new suit – an unnecessary jump – is therefore a splinter. For example, 1♠ - 2♥ - 4♦ shows a singleton or void in diamonds, with at least four card support for responder's hearts.

-- Ray 

Better Bridge in 5 Minutes. Guaranteed! (or the next one is free)