[Trinidad]

I am with Helene and Phil. 4NT simply does not exist after North has limited his hand. North suffers from controlfreakeritis and seems to want to be the captain in every auction. After his 3♣ bid it is simply his job to tell partner what he has, if partner wants to know.

As a bridge doctor, I would prescribe to North:
Before every bridge session write down 10 x "Partner can be trusted to make his own decisions. I do not need to do everything myself."

Rik

[gszes]

Responders decision to bid 3d then 3s (after 3h) shows a much stronger hand than
a direct 3s over 3c. QJTxxx xx Kx xxx would easily try 3s way too cowardly to
pass 3c. Once opener realizes responder has extra values their hand really needs
nothing more than 2 top spades to make the 5 level safe and responder has at
least twice that power at their disposal so a slam search seems warranted.

The 3c bid is indeed limited but there is still a significant difference between
top and bottom of the bid and fit vs no fit this hand happens to be near the tippy
top with a spade fit and a hand that is tough to describe after responder bids 3s
(which hugely increases the odds of them having great spades and not much if anything
in diamonds since they might have preferred 2n with not so good spades and reasonable
dia "stuff".

[jallerton]

gszes, on 2014-December-19, 08:29, said:

Responders decision to bid 3d then 3s (after 3h) shows a much stronger hand than
a direct 3s over 3c. QJTxxx xx Kx xxx would easily try 3s way too cowardly to
pass 3c. Once opener realizes responder has extra values their hand really needs
nothing more than 2 top spades to make the 5 level safe and responder has at
least twice that power at their disposal so a slam search seems warranted.

Playing 3♠ over 3♣ as weak is a poor idea as it narrows the bidding spectrum, having as it does a similar effect to only using half of the width of the page when posting on BBF.

gszes, on 2014-December-19, 08:29, said:

The 3c bid is indeed limited but there is still a significant difference between top and bottom of the bid and fit vs no fit this hand happens to be near the tippy top with a spade fit and a hand that is tough to describe after responder bids 3s (which hugely increases the odds of them having great spades and not much if anything in diamonds since they might have preferred 2n with not so good spades and reasonable dia "stuff".

Yes, there is a significant difference, but if Opener has decent secondary spade support, he shows that by means of reverting to Responder's suit at the first opportunity. This concept is sometimes referred to as a preference bid. When a player fails to make a preference bid, it is often possible to draw an inference about the lack of support.

[Lovera]

I think at this time being RKCB a convenction that substuites classical Blackwood its applicability must be clearly definited to avoid misunderstanding with partner considering all case of bidding possible and establishing rules to say if is or not RKCB (and in that case considering 4NT how quantitative) otherwise holding ambiguity may not be helpful and to be a point of weakness for RKCB, bye.

[Lovera]

scarletv, on 2014-December-17, 17:08, said:

This is how the bidding continued ...

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Althoug North after diamond J for Ace must play all its hearts and have a possibility of fullfil the contract with a pseudosqueeze in the minor (if West unblock diamonds).(Lovera)