| Board 14 East Deals None Vul |
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NS 6♣; NS 5♠; N 4N; S 3N; EW 2♦; EW 1♥; Par +800: EW 6♦×−4
| West | North | East | South |
| Pass | 1 ♠ | ||
| Pass | 2 ♣ | Pass | 3 ♠ |
| Pass | 4 ♠ | Pass | 4 NT |
| Pass | 5 ♦ | Pass | 5 ♠ |
| All pass |
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| Board 14 East Deals None Vul |
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NS 6♣; NS 5♠; N 4N; S 3N; EW 2♦; EW 1♥; Par +800: EW 6♦×−4
| West | North | East | South |
| Pass | 1 ♠ | ||
| Pass | 2 ♣ | Pass | 3 ♠ |
| Pass | 4 ♠ | Pass | 4 NT |
| Pass | 5 ♦ | Pass | 5 ♠ |
| All pass |
a) a difficult hand for ACOL given South wants to show club support but not lose the possible 6-2 spade fit. I think 3S is correct.
ReplyDeleteb) But over 4s I think South should give up as it already have fully stated its hand. A good technique for evaluating slam potential is called "perfect minimum". If slam is on with a perfect minimum then u should invite. Give pard KS, QS, AH, then he cant have the KC or the AD
c) look at the cards u need to find out about, KS, QS, KC. 4NT not RKCB doesn't help at all.
d) basically South was using 4NT as an attempt to get to slam, whereas it is supposed to be used as a technique to stay out of bad slams. If South wanted to go on 5S is probably a better bid.
This is a trickier problem at MPs than IMPs. At IMPs you should be willing to forego a little on game bidding in order to get to a good slam when it is on. That is, at IMPs you don't mind so much if you end in 5C rather than 4S (assuming both make).
ReplyDeleteThe perfect minimum idea is an old one but a good one. It is sometimes called the Culbertson Rule - Ely Culbertson was very early on one of the forefront experts at bridge. Interestingly here a perfect minimum for a club slam is less than for a spade slam - sKx hAxx dxxx cKxxxx would make a very decent club slam but not such a good spade slam.
An interesting hand for LTC imperspicuity.
ReplyDeleteBidding. 1c* - 2c**
2d*** - 2s****
2nt^ - 3h^^
3s^^^ - 4d^^^^
4nt# - 5h##
6c
* <= 6 losers any shape
** <= 8 losers 5+ clubs. If only 5 clubs 4 diamonds.
*** Relay
**** Has a 3 card major. Denies 33 majors
^ Relay
^^ 6+ clubs 3 hearts
^^^ Relay
^^^^ 6 clubs 3 hearts 3 diamond 1 spade. 10 total possible losers
# RKCB. Clubs
## 2 key cards without Q clubs
With a 4.5 loser hand after norths response showing a <=8 loser hand they know theoretically with a good club fit north needs only a little extra for possible slam and can bid to 5 level (18-4.5-8 = 5.5 level) "safely". There is also a possible spade fit and spade slam although with norths 2s bid a club slam protects the Kh from initial lead. Using relays south determines norths shape and possible total losers. If there were sufficient bidding space South would determine norths exact loser count but this is not possible for this hand. By determining total losers south knows that north must have either A and A, or A and K; or KQ, Q; or AQ, Q for their 2c bid outside the spades suit.
After norths 4d bid South has a similar dilemma to an Acol player to explore slam in clubs (spades no longer an option with unfavourable fit) but with more information and different concerns. The problem is that with norths shape it is clear that the key to make slam is having at least one of two missing aces and this can't be determined using RKCB unless north has 2 key cards. If the Kc is missing there is a ~50% chance of slam success if north has Ad or Ah. Using 1430 South can still stop in 5c if north has 1 key card but has no option but to continue to failing 6c if north has 0 key cards.
An alternative TLC imperspicuity bidding sequence would have helped solve this dilemma but South has to recognise the significance of diamond A or heart A after norths 2c response
1c* - 2c**
2h*** - 2s****
3d^ - 4c^^
4d^^^ - 4nt^^^^
6c
* <= 6 losers any shape
** <= 8 losers 5+ clubs. If only 5 clubs 4 diamonds.
*** Asking bid in hearts, slam interest
**** No first,second, or third round control
^ Asking bid in diamonds
^^ First round control (void or A). Do not have AK or AQ
^^^ 2nd asking bid in diamond
^^^^ A with 3+ diamonds
With this alternative bidding sequence South is able to determine that north holds the key A of diamonds and slam is at worst a 50% chance. For their responses north must have either a 5431, 6331 (10 total losers) or 5440,6430, or 7330 (9 total loser) "shape.
If they have either of the first two shapes they must have Kc for their <=8 loser response as there are no honours in hearts and have denied having AK or AQ of diamonds. If they have last two shapes then their only honour may be the A diamonds in which case the slam will rely on finesse of Kc (or falling under A) and spades splitting 43. So overall a better than 50% chance of making.
South still has to decide if today they will take the chance but at least they can stop in 5c if they wish.
Not a bad 19 or 22 pt slam when it makes.
At end of day, ACOL is a pretty basic system, and will have no hope of competing with big club/relay systems at slam level with distributional hands. Here, at MPs, north didn't even know about the club fit as south had to focus on the best MP game.
ReplyDelete