Never lie, didn't your mother tell you?

Partner opens 1♠ and you have:



What is your bid?

If you play pure Jacoby 2NT, you can't, you don’t have 4 trumps.
If you play 2/1, can you really bid 2♦ on that suit?  Maybe you can, but our style is a good 5-card suit, a source of tricks, not Jxxxx for example.  The only exception over 1♠ would be if the suit was hearts.
As for those who would bid 2♣ just to create force, how can opener re-evaluate his hand or honours in clubs if 2♣ could be artificial?
So we adopted Fred Gitelman's advice, 2NT natural, game forcing, stoppers everywhere outside opener's suit.  Simple, direct, very, very efficient.  If you have a fit in opener's suit, it can be only 3 cards.  So let's see how it works.



Wow, we have a double fit.  What do you do?  Do you give fit in spades or in diamonds?  Didn't you read somewhere that a 4-4 fit is better than 5-3 because, on the 5-3 suit, you will be able to discard losers?  So you decide to give fit in diamonds.   But wait… like in TV ads.
If you give fit in diamonds, partner won't know you have a spade fit.  If you have possibilities for a grand slam and it is you asking for key cards in diamonds, you will learn maybe that partner has AK of spades, but what about the Queen of spades? 
This is where bridge is so exhilarating: thinking, examining possibilities, ways of extracting information from partner, even if you have to lie to her.  So, you think, I have to fit in spades so I can ask for keys in spades, for I will learn, with King ask, if she has the diamond king.  But if I fit in spades and partner goes key card… but wait.  Partner cannot go key card, she has no control in clubs.  So if you bid 3♠, partner will bid 4♠ if she has a minimum.  If she has extras, she will have to bid something else saying: I have a good hand.  But wait, you say.  What if she bids 4♦ over 3♠, to show a diamond control, but no club control?  I say she can't.  We play that over 3♠ GF, 4♦ shows controls in both clubs and diamonds, as 3NT is available to say: Please cue 4♣ if you have a control there.  Simple, no?  Brilliant, I think.

So


Super! Partner has no control in clubs, but she has extras, which means at least a king more than a minimum.  So now all is in place.

Control your heart beat, relax, breathe in, check everything again, count: 5 spade tricks, 1 heart trick, 3 diamond tricks (3-2 break), 2 club tricks, 1 heart ruff in dummy and 1 club ruff in hand = 13.  If trumps don't break, heart finesse will have to work.  You reach out leisurely, take the 7♦ card in your hand and slowly place it on the table.  It is not everyday you bid a grand slam, so savour the moment.  And when is the last time you establish a false trump suit to reach a grand slam in another suit?

After putting the 7♦ card on the table, you look around the room, trying to find a pair that would bid like you did (isn't he so full of himself!).  You can't find one.  Everything worked like magic, but wait…   Partner is thinking (she always does that to me).  She examines her hand.  Every second that passes kills me.  Finally, finally, she puts the pass card on the table and you come back to life.  Everything broke nicely,  +2140.


But wait ‼!  The heart finesse was on, so every card pusher could bid and make 7♠.

Don't lie, my mother told me, or you will get punished.