Surprising and strange statistic

[akwoo]

Here is one where I have to guess at the auction, it is the only way I can see we got there:

 

[hv=pc=n&s=skj83hqtdq943cqt7&w=sq765hj842djtck62&n=s9hk63dak7652c543&e=sat42ha975d8caj98&d=n&v=e&b=9&a=1dd1s2hpp3dpp3hppp]399|300[/hv]

 

We got it one off for a 33% score. Six other pairs. Four bid and made 2 or 3♦, two went off in 4♦.

 

At MPs, South must double 3♥, showing balance of power without values for game. North can judge to pass rather than bid 4♦.

 

Think of it this way. If E/W play 3♥ undoubled, you are booked for a bad score.

 

It's possible 3♥ makes; then you're -140, which is at most 25% (and probably a 0) for you since, if the other people your way are down 2 undoubled or down 1 doubled in 3♦, it's still only -100. If they make, the double turns -140 into -730, but the difference between -140 and -730 isn't very many matchpoints, maybe 25% of a board at most.

 

If 3♥ goes down undoubled, then you're +100, but when 3♥ goes down, the other pairs playing your way are probably making 3♦, which is +110, so the +100 is still only 25% (and maybe a 0). But now the double turns your +100 which was a bad score into +200 which is a very good score (beating +110 or +130 or +150), probably a gain of 50% of a board or more.

 

So a double costs not so much when it's wrong, but gains quite a bit when it's right. (Note, at IMPs, it's the opposite; the double would cost quite a bit when it's wrong but doesn't gain much when it's right.) Hence the odds favor doubling.

 

There's a classic book explaining this logic and how to apply it to various situations by Kit Woolsey titled "Matchpoints".

[AL78]

At MPs, South must double 3♥, showing balance of power without values for game. North can judge to pass rather than bid 4♦.

 

Think of it this way. If E/W play 3♥ undoubled, you are booked for a bad score.

 

It's possible 3♥ makes; then you're -140, which is at most 25% (and probably a 0) for you since, if the other people your way are down 2 undoubled or down 1 doubled in 3♦, it's still only -100. If they make, the double turns -140 into -730, but the difference between -140 and -730 isn't very many matchpoints, maybe 25% of a board at most.

 

If 3♥ goes down undoubled, then you're +100, but when 3♥ goes down, the other pairs playing your way are probably making 3♦, which is +110, so the +100 is still only 25% (and maybe a 0). But now the double turns your +100 which was a bad score into +200 which is a very good score (beating +110 or +130 or +150), probably a gain of 50% of a board or more.

 

So a double costs not so much when it's wrong, but gains quite a bit when it's right. (Note, at IMPs, it's the opposite; the double would cost quite a bit when it's wrong but doesn't gain much when it's right.) Hence the odds favor doubling.

 

There's a classic book explaining this logic and how to apply it to various situations by Kit Woolsey titled "Matchpoints".

 

Yes I understand the concept of the pairs double, and that risking doubling them into game is worth it for the chance of getting +200 or +300 when it looks like we have been outbid. I have done souch doubles before, unfortunately rarely with success (they make their doubled contract usually). Here's one I completely misjudged:

 

[hv=pc=n&s=sk865ha962da84ck3&w=sa4hjt743dkjt7c75&n=sq9732hqd52cqj962&e=sjthk85dq963cat84&d=s&v=b&b=7&a=1n2c2s3h3sppdppp]399|300[/hv]

 

2♣ showed hearts and a minor 5+4+ shape.

 

I thought the balance of power was either level or our way, and I decided to go for the +200, thinking the room would be in 3♥ our way, and this is a pair who are notorious for aggressive bidding. It wasn't to be, this was a bottom when 3♠X made with two overtricks (should have been +1 but that is irrelevant). Most were in 2♠ undoubled, two found the game and one went off. If I don't double, we get a near average, or 71% if we defend optimally and hold it to 10 tricks, so my pairs double was quite expensive.

 

This was with a different regular partner than the other hands I have posted. It was a rare win, just over 62%, and exceptional in that I declared 12 times out of 24 boards. My declarer play was 72%, my defence on lead (four times) 36% lol.

[akwoo]

Is the room playing 2-suited overcalls of 1N? If not, I don't see why you're expecting folks to find a bid over 2♠.

 

Was 2♣ specifically 5+♥ 4+ in a minor or could it be the other way? Was West minimum for 2♣ or could be even weaker? I have a feeling you and your partner are not quite on the same wavelength about 2♣.

[AL78]

Is the room playing 2-suited overcalls of 1N? If not, I don't see why you're expecting folks to find a bid over 2♠.

 

Was 2♣ specifically 5+♥ 4+ in a minor or could it be the other way? Was West minimum for 2♣ or could be even weaker? I have a feeling you and your partner are not quite on the same wavelength about 2♣.

 

Quite a few people do play defences like Astro or Landy, I;'m not sure how many were on that evening.

 

The 2♣ could be 5-4 either way, I took a chance she held a longer major. I maybe should have realised that holding a double fit, defensive prospects were not that great. I did expect a bit more for the overcall, a double figure HCP count at least unless very distributional, bearing in mind the vulnerability.

[akwoo]

Over 2♠, you should have an agreement about what bid asks for the minor - one of double, 2N, or 3♣ should do that - the bonus is that any of those bids shows strength or shape, so it takes East off the hook when it comes to doubling 3♠ - it's West's job now.

 

If West had held ♠Axx ♥Axxxx ♦xxxx ♣x the double would've been brilliant.

[Zelandakh]

Over 2♠, you should have an agreement about what bid asks for the minor - one of double, 2N, or 3♣ should do that - the bonus is that any of those bids shows strength or shape, so it takes East off the hook when it comes to doubling 3♠ - it's West's job now.

Typically Double is the equivalent of the relay, asking for the longer suit, and 2NT asks specifically for the minor. There are some minor nuances that can be done in addition but I think that is the easiest general agreement for the method as it essentially works in more or less any auction.

[AL78]

The declarer drought continues. I sat in with the beginners this evening to make up the numbers. 14 boards, declared once, my partner declared twice. Average HCP count our way 9.57 and 9.43. The good thing was despite defending 11 out of 14 hands, we had something to defend with, and even though I was partnering a 1st year student, we defended well, and we ended up second with 63.7%. If the helper hadn't encouraged her to bid the spade slam that went off on a 5-0 spade break (6NT makes thanks to the rest of the layout being favourable), we might have won.