Problem N°1:

  This illustrates a common problem - dealing with high level intervention. Given a free run South would respond 2 planning to introduce the heart suit on the next round.

 With so many rounds of bidding now swept away by East's intervention South has to decide how best to show his hand. Of course some degree of luck is required as we are going to bid applying some principles that are fine in theory, but can sometimes be overturned by the actual layout.

 In the modern age partner's opening bid might be made on a very modest hand, but if we make the assumption that it is unlikley to contain values in diamonds then you realise we are bidding with a 30 point pack and in that context have a terrific hand, one where we are entitled to think in terms of a slam.
 

 We can reject any idea of doubling - at this level that has to be for penalties (although I know a few players who think negative doubles should go all the way to at least this level!).
What about bidding one of our suits?

 Bidding either of them risks missing a much better fir in the other, apart from the obvious point that partner is almost bound to pass a bid of either 5 or 6.  
 

 Bidding 6 would show the first round control, but mean we could only play in clubs at the seven level, and that is a bit much.

 That leaves us with one further possibility, to bid 5NT. The idea of using the bids of 4NT and 5NT to show two suited hands is well established (and can sometimes be applied to 3NT in certain situations). Here it clearly shows a powerful two suiter with hearts and clubs and by inference a diamond control.
 

 The only thing left to consider is what action to take over partner's response, be it 6, 6 or 6. The answer must be to pass. The opponents have made us guess at a high level. If we happen to have a grand slam available so be it - all we can do is congratulate East. 

Trine Binderkrantz: 5NT

 This is a very interesting hand, and a lot depend on partnership agreements.

 The first thing I would say, is that I don't think double is an option - it should show a more balanced hand and partner will pass on too many hands where we can make slam, and only gain 5-800 against 5.

  Without specific agreements I would guess that 6 here should show spade support, interested in grandslam and 5NT would be "pick a slam". I would therefore bid 5nt on this hand.
 
 It is worth a partnership discussion though... I think that 6 should be spade-sup, going for the grand with 1. round control in diamonds

  5nt should have two meanings: a) take-out, pick a slam, with distribution something like this (the two unbid suits and spade tolerance). b) It could be spade support, going for the grand, but without 1. round control in diamonds.

  Over 5nt opener will pick a slam... If opener has a long spadesuit and therefore will rebid spades (), opener should cuebid 6 on the way with 1.round control. This way we can reach the grand if 5nt was option b).

  If opener bid 6 or 6 and I now bid 6it is obviously the grand slam invitation without diamond control. This does not cover all of course - but that is why someone invented preempt .

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Gabriel Chagas: 5NT.

  I think the Pass is forcing, double would have shown cards & 5NT a two coloured hand, which was the winning option. In Miguel Villas Boas case, Joao Paulo Campos with QJxxxx, Kx, xx, AQJ, bidded 6, the best contract. 

 

 If the openning bid would have been  5, DBL, Pass,  now 5NT in the last position, would have been RKC. Remember: here a Pass isnt  forcing, its final!!. Thats why the partner´s double  at the fifth level virtually requieres support in all the suits.

 Then 6 and 6 are alternative contracts and 6 an invitation to 7.

 Well, nothing but ideas .... A tough game ... but ... As you know, this mutable life, among many things, can be very beautiful ....

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Pablo Lambardi: 5NT.

5 NT. I hope my partner take it as unusual NT and not al some kind of question in spades. There may be 6 or 7 in any of the other 3 suits or we can fall to 5. As I see no way to find out, I opt for the middle -  I will play 6 in the suit my partner choice.

 The alternative = DOUBLE,  could be OK if the opener has something like:

 KJxxx  xx A10x Axx  

but it wont take us to the better score if he has a balanced hand because he will  Pass over 5X and we have 6... in our side. 

For example Kxxxx Kxx Kxx Ax gives us very good chances for 6.

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Eric Kokish: 5NT.

 Hearts and clubs and small overbid, based in part on the VUL 5 bidder having most of the honors in his suit.

 I'd like to tell you that 5NT also show two spades, but it doesnt. Dont let anyone tell the differently

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Barry Rigal: 5NT.

 I don't --and I'm bidding it. It is not a grand slam force (6 is the only clear spade agreement call) 'do something intelligent' maybe! 

 

I think I'll pass partner's response unless he cue-bids 6 in which case I opt for 6.

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Marcelo Castello Branco: 5NT.

In these situations the voice of 5NT should be treated as "partner please, pick a slam" .

Thus, on 5NT, North must select a suit for 4 cards.

 If he doesent have one,  he can repeat spades with a good suit or bid 6/  with 3 cards if the spades are not good enough, because obviously the partner has no spades support. In the latter case, say 6NT or pass, with AK of diamonds (rare).

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Agustín Madala 5NT.

 As Jack Nickolson in "SomeOne Flew Over the Cuckoo's Nest".

No bid can show my hand. I wish I could say Double= "forcing my partner to show his hand" to help me make a correct decision, but I doubt he would understand.

 This would happen with all balanced or semi-balanced hands , where perhaps we can win 7 in all the suits.

 5NT is ambiguous, it could be a very strong hand with spades support , but with no first-round control in diamonds.

While I dont know what I will do over an eventual 6, 6, 6 or 6 from my partner, I'm trying to think about the first decision I have to take.

After his response I'll have to think it...again.

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John Carruthers: 5NT.

 I would bid 5NT (pick a slam) to ensure that we get to play rather than defend.  If I double, partner will pass with any balanced or semibalanced hand.

 Since I am the one who knows we should be on offence rather than defence, 5NT seems the choice. We may not make it, but I can't bear being plus 200-500 when we are cold for a slam, so it's worth taking a chance.

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Brent Manley: Doblo.

 Showing "transferrable" values: Whatever partner does, my hand is suitable.

 

 The only question is whether to raise to slam if partner bids 5 or 5. I probably would in the belief that the auction will be similar at the other table and that players tend to be aggressive.

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Nadia Bekkouche: 6.

 If i have the agrement, that 5NT is the 2 unbid suits, that would be my bid , but i dont think that is the common agrements.

  5NT could ask for aces,with first round control in diamonds and spade support, and 6 could be a good raise in spades without first control in diamond. So i unfortunately has to gues a contract..

 My gues and bid will be 6, if somebody smack the pony i probably will run in 6, hoping to show hearts and some support for spades.

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Miguel Villas Boas: 5NT.

I had this hand in the Transnational and my bid was 5NT, Joao Paulo answered 6 so I passed.

After the game he told me he thought 5 NT was for aces, and his 6 = 1 Ace.

I think this is must be a partnership agreement.  If 5NT is for asking aces, then the bid is Double.

 After the event we arranged  that 5NT should be a two colored hand, and 6 a strong invitation to 7.

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Juan Manuel Rueda: 5NT.

 After East's voice in a vulnerable position...we are in slam and now we have to find the triumph suit.

5NT solves the problem showing a sharp two-coloured hand,  & ,  that can not be interpreted as Josephine because 6 is a possible voice.

Finally, my partner in an  inspired day,  with a solid spade suit and honors in my suits, will bid over my 5NT, 6 inviting to 7 with KJxxx Kx  xx  AQxx or with KQJ10xx Kx  Ax xxx.

 Was this a hand From the Worls Champioship?