We had this - very rare - monster the other day at the Gazette in Balham:
Feast your eyes because you won't see this kind of hand very often. However, you well might, and you should have some idea of how to deal with it. You'll probably find nothing in textbooks, so here goes...
At the table (Both Vul) it was opened 6C! Perfectly reasonable: one loser, 12 top tricks in Clubs.... But the auction then went...
6C - 6S - P - P
7C - P - 7S - X!
7SX duly went off 3 for 800 a fabulous save as 7C actually makes (partner having the Q D's!), which would have been 2140! Even 7 off doubled (2000) would have been good for them. So how can we improve on this measly +800?
Looking at the hand again we can see that despite 6 C being cold it only has 17 HCP, thereby disproving that all slams need to have a combined 32+ count! It follows that there are another 23 points dotted around the other three hands. It is also true that if you have a 10 card suit, your opponents may well both have fairly silly hands themselves. They are therefore almost certainly going to join in the bidding themselves. Opening 6C - while perfectly reasonable - does let a rather massive lioness out of the bag. You could try opening 2C - on the grounds that Game is a certainty (!) but they will still be getting into the auction somewhere if they have any blood in their veins. So - what's to do? How can we improve this outcome?
As I said, you only actually have 17 points plus 2 voids. So where are the other points and suits? If partner has them we could get to a possible 7NT. If the opponents have them we don't really want to disclose our full potential too early, do we? What about opening 1C? Will that be passed out? Extremely unlikely. The bidding will come back to you. They WILL be bidding. You will get another chance. By then you should have some idea of what's going on. Plus your softly softly approach opens up the possibility to, as they say, catchee monkey. Take a look at the back of the 7C card. Making is 2140. Doubled and making it's 2330. Redoubled and making it's 2660. Any of these are miles better than 800. Your strategy should be to bid as if YOU are sacrificing against THEM!
1C - 1S - X - 4S
5C - 5S - P - P
Almost whatever happens now is to your advantage. They pass, you get 1370. They double, you get 1540. (DON'T Redouble!) Most of the time - I venture to suggest - they'll bid again - 6S. Now is the time to hold your nerve. Bid 7C. They might be making 6S. Who can tell? More importantly, you might make 7C. Now - hopefully - you have them. You have sprung the trap. Good opposition may well now bid 7S, and you are back to square one. But there's always the chance you will now be doubled. Still do NOT re-double. It will be impossible for them to visualise that you have such an extraordinary and incredibly rare hand. But if you re-Double you make it a certainty they will bid to 7S because you just told them to. Just make the doubled Grand Slam and quietly write in the score.
This method of bidding weird hands is known as Creeping. It is a standard ploy to get the opponents to feel they have pushed you too far. Instead, you are just where you always wanted to be.