What is Jacoby? A bid of 2NT over 1 of a major from Partner, showing a good raise in Partner's major. It should have 7 or less losers generally, unless the bid is made after an initial pass, when it could possibly have 8 losers. It will NEVER have a flat 4-3-3-3 hand with the 4 cards in Partner's Major but equally, shouldn't have a singleton or void, when you should use a splinter instead of the 2NT bid.
|1H||2NT||2NT guarantees (if not a passed hand) 4+ hearts, and
a game force.
|3C**||3S||3C is a trial bid, and asks for help in clubs - 3 small clubs will generally deny help! 3S is a very good hand, probably a cue bid in spades and will therefore offer help in the club suit|
|3NT||4H||3NT must be 15-19 points, otherwise, you will bid 4H. 4H is NOT a sign off, if you wanted to sign off, you wouldn't have bid 3S in the first place!|
** A possible use of the 3C bid.
The hands might be:
|♠ K Q||♠ A x x|
|♥ K Q 10 8 2||♥ A J 7 5|
|♦ A K 8||♦ 7 4|
|♣ 8 4 2||♣ A K J 6|
On these hands, you can make 7H!!
3♣ is a trial bid, and 4♦ is a splinter (probably a singleton), with help in the club suit also.
Note: 1♠ .. 2NT .. 3♣ as a sequence is forcing to game, so 4♦ cannot meaningfully be anything but a splinter
Normal Jacoby sequences:
|3♥||4♥||Simply bidding game|
|3♣||4♥||Whatever the 3C bid meant, 4H shows a minimum, and is NOT forcing|
|3♣||3♥||Seeing as 2NT is forcing to game, this 3H bid must be stronger than the 4H in the above sequence. It is giving West the opportunity to make a cue bids.|
|4♥||The 4H bid shows no additional values, and is to play.|
|3♥||Pass||The 2NT bidder can pass, when he/she has already passed on the first round!|