[steve2005]

6C-1
Can someone explain why the weak hand is using KC. just show a control.
Oh needs a 1st rd control to show, but is so week uses KC instead.
what baloney. Anyone have a better explanation?

This from just declare so everyone in hopeless contract.

[virgosrock]

steve2005, on 2018-June-08, 04:37, said:

6C-1
Can someone explain why the weak hand is using KC. just show a control.
Oh needs a 1st rd control to show, but is so week uses KC instead.
what baloney. Anyone have a better explanation?

This from just declare so everyone in hopeless contract.

can't see the hand steve. firefox, windows 10

[Stephen Tu]

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[virgosrock]

Stephen Tu, on 2018-June-08, 05:18, said:

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GUBizzare steve2005. It just has a 4C bid. Not sure what flights of fancy it had. your 5H, i forget what is even kc and void. 5NT? if so it may have passed

[johnu]

5NT wasn't a signoff. GIB N assumed S had 5 keycards (5♥ = 2 or 5 keycards) for the jump shift and was trying to get to a grand slam.

As for why GIB jumped to 4NT (with potentially worthless spade honors)? Duhhh, this was GIB. Enough said.

[steve2005]

johnu, on 2018-June-08, 11:26, said:

5NT wasn't a signoff. GIB N assumed S had 5 keycards (5♥ = 2 or 5 keycards) for the jump shift and was trying to get to a grand slam.

As for why GIB jumped to 4NT (with potentially worthless spade honors)? Duhhh, this was GIB. Enough said.

Just a reminder this is just declarer so it is 2 Gibs doing the bidding. (not me)

My question how can a hand as weak as North's justifying KC no matter what South has shown?

[smerriman]

steve2005, on 2018-June-08, 17:15, said:

My question how can a hand as weak as North's justifying KC no matter what South has shown?

Basic GIB bids 5♣ (4+♣, 10+ total points) instead of keycard. 4♣ just shows 4+♣, 6+ total points.

I guess GIB thought there was a chance of slam and calculated that the probability of a 5♥ response was low enough to make it worth the risk.

[virgosrock]

smerriman, on 2018-June-08, 17:44, said:

Basic GIB bids 5♣ (4+♣, 10+ total points) instead of keycard. 4♣ just shows 4+♣, 6+ total points.

I guess GIB thought there was a chance of slam and calculated that the probability of a 5♥ response was low enough to make it worth the risk.

Even if 5H probability is low, the GUBidding is Bah Humbug

[smerriman]

virgosrock, on 2018-June-09, 05:17, said:

Even if 5H probability is low, the GUBidding is Bah Humbug

Why?

I generated 500 hands of the form:
- 5+ diamonds
- 4+ clubs (but not more than diamonds - jump shift into a 3 card minor is I guess possible but don't know if GIB does it)
- <= 3 spades
- 18-21 hcp, 19-22 total points

and compared the results of a 4NT ask over the book 5♣ bid.

On 244 occasions (48.8%), you get a 5♣ response anyway which you will pass; there is no difference.

Only on 12 occasions (2.4%) would you get a 5♥ response. 5♣ only actually made on 5 of those; the rest you go down an extra trick. Average loss was 3.58 IMPs.

On the other 244 occasions (48.8%), you're in 6♣. On 12 occasions, both go down. On 125 occasions, the slam makes. On 107 occasions, 11 tricks is the limit. Average *gain* was 1.15 IMPs.

Overall, bidding Blackwood instead of 5♣ is 0.48 IMPs better.

So, a win to GIB as far as I can tell.

(NB - I didn't take into account void-showing responses, if applicable, or cases when opener would want to raise 5♣ to 6♣ which would have a big influence - but I would have thought 5♣ is pretty much a sign off.)

[virgosrock]

smerriman, on 2018-June-09, 19:29, said:

Why?

I generated 500 hands of the form:
- 5+ diamonds
- 4+ clubs (but not more than diamonds - jump shift into a 3 card minor is I guess possible but don't know if GIB does it)
- <= 3 spades
- 18-21 hcp, 19-22 total points

and compared the results of a 4NT ask over the book 5♣ bid.

On 244 occasions (48.8%), you get a 5♣ response anyway which you will pass; there is no difference.

Only on 12 occasions (2.4%) would you get a 5♥ response. 5♣ only actually made on 5 of those; the rest you go down an extra trick. Average loss was 3.58 IMPs.

On the other 244 occasions (48.8%), you're in 6♣. On 12 occasions, both go down. On 125 occasions, the slam makes. On 107 occasions, 11 tricks is the limit. Average *gain* was 1.15 IMPs.

Overall, bidding Blackwood instead of 5♣ is 0.48 IMPs better.

So, a win to GIB as far as I can tell.

(NB - I didn't take into account void-showing responses, if applicable, or cases when opener would want to raise 5♣ to 6♣ which would have a big influence - but I would have thought 5♣ is pretty much a sign off.)

very enlightening smerriman. I gave it more thought. If GUBBO bids 4C then likely opener bids 4S denying heart ace, denying diamond ace and unless 4S is some sort of delayed support for spades and is interpreted as a cuebid GUBBO should subside in 5C. (close to 100%).

victory of common sense over common science? major point being 4C provides room for investigation rather than bash in to simulations. PLUS the option of 4NT is still there after 4S if GUBBO does not trust pard.