Sunday, 27 November 2011

Making a sacrificial bid

IMP pair, nil vul, N opening.
North
S ---
H 96
D 84
C AQJT98762

South
S AJ9852
H AKQ72
D -----
C K4

A clear 7C you would say, despite that my (robot) opponent is stupid and didn't make any signal for his long solid C. A suitable calling should be like this
1C[0] - X[1] - 1H - /
3C[2] - 3D - 3S[3] - 5D[4]
/[5] - / - X[6] - /
7C A.P.
[0] - solid C (solid 6+) or 13P+, 3+C
[1] - t/o double
[2] - very solid C (7.5 winner) and weak hand
[3] - 5-4 or above good major suit, 16+, GF
[4] - D support
[5] - DOPI, pass = 1 A (probably C)
[6] - D first control, decide between 5DX, 6C or 7C
OR like this if you like the gambaling conventions
3NT[1] - / - 4H[2] - /
5C[3] - / - 7C[4] A.P.

[1] - Gambaling 3NT, solid minor with no side power
[2] - promising power, 5+ strong H, slam interest
[3] - the suit is C
[4] - To play

...and the stupid robot play like this
/[0] - 1D - X[1] - /
2C[2] - 2D - 4D[3] - 5D
6C [4] A.P.

[0] - unknown response by bot
[1] - t/o double
[2] - 4+C
[3] - variation of splinter
[4] - without detailed discussion

What makes 7C biddable is that:
- A long, solid C with 9 winner including C K
- Voiding D
- A fine 5-5+ major with first control

So which one you would prefer? Difficulties are always experienced when you hold a long C if you use natrual/SAYC system because 2C is artificial strong 2C but not weak 2.
Instead, we give 1C another artificial meaning [to show long C] followed by recall signal. The resulting C is better than usual weak 2, or even exceeding 3X weak call.
On another side, South has to show his fine distribution and support. A 1H-3S is used in the first bidding approach, but for the second and third approach, we can only show "promising power" without detail of the hand due to the lack of biddable space.

For me, I prefer the second one since the 3NT suscessfully blocks almost all preemeptive bidding from the opponents as they failed to told their partner that they have a long D suit.

In reality, East holds:
S KQT
H JT4
D AKQ76
C 53
With opening power, his is willing to call out his diamond suit, and W is able to sacrifice to 7D (which is ~ -1100, less than 7C= which is ~-1400) with 11 D and some side power. E-W can reach 7DX-5.

Since West is the fourth bidder, it's not so possible for him to call out his D suit (and he's not even able to bid weal 2 2D opening). It relies heavily on how East showing his D hand. On the first and third approach the opponents reached 5D, but none of them reached 7D because E lacks confident.

In fact, whe you hold East's hand, knowing that North have a long solid C while South have a bunch of winner on major with first control, and South voids D (because he have first control but NOT D A), then West would have no power other than JXXXXX diamonds, by the law of total tricks, it's certain that 7D would work.

In reality, 6C+1 is made, 2 table reached 7C=, 1 table 7HX= (I'm surprised by this one), 1 table 7DX-5, 5 table 6C= with some table playing other contract and lose quite a lot of IMPs.

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