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03-20-2006 12:06:29

Chapter 13

Balancing Over a 15-17 Notrump

Summary

Play a system such as DONT, Brozel, or Woolsey, that allows you to show most two-suiters.  Do not play a system where double shows count.

A computer study of many deals shows you should think Always Balance.  Vulnerability and length of the longest two suits are important.  Having a singleton (or void) is a plus, but is not a necessity. 

With nine cards in two suits and a bid that shows two suits, always balance.  You expect to make over 50% of your bids.  Making is not sensitive to balancer's point count.  How well you do depends on vulnerability — Both vulnerable you would do better passing if partner would lead your suit.

To bid or not to bid on less distributional hands can be a matter of personal preference.  Possibilities: 

If you choose Always Balance (I do), then second seat simply bids to the best spot.  Second seat does not bid to the Marty Bergen limit, and second seat does not attempt to reach game.  Long ago the rule for raising a friend's three-level preempts was game in hand plus trump support, and that should be rule here.  If you can count nine tricks, you can invite, and with ten you may bid game.  If you want a minimum suit count for advancer's bid, choose five or six.  If advancer has many points, then fourth seat is simply bidding his hand.  Defensive points should be between 15 and 25, and 20 is a much better guess than 25.

Against weaker notrumps, I choose Always Balance.  The above applies.  An experiment several years ago showed that the chances for game for either side after a 10-12 notrump was 30%, which means your chance is about 15%.

Balancing over a 15-17 Notrump
Vulnerability
Pattern None N-S E-W Both Comment
6 + cards Always Balance Double dummy numbers say no when both are vulnerable.  Partner will not lead your suit.  Balance.
5-5-x-x If everyone else is passing, you should play DONT, otherwise Woolsey.  With both vulnerable, numbers say bid.
5-4-x-x With both vulnerable, always balance = 43%.  Count is starting to matter.  You make over half the time, so balance.
4-4-x-x Always Balance Have values Count matters.
5-3-3-2 Balancer treats a 5-3-3-2 pattern as a one-suiter.  Results are similar for any five-card suit, or a three-of-the-top-four suit.

Larry Cohen Chart Logic

We could have anticipated that results depend on the four vulnerability conditions, and that the most unfavorable vulnerability is Both.  Assume: 

Then:

Here is one of the four charts Larry Cohen might make to show this.

Chart for 13 trumps - They are Vulnerable
We play the hand in 1NT They play the hand in 1NT
Our # of Tricks Our Score Their # of Tricks Our Score
9 +150 4 +300
8 +120 5 +200
7 +90 6 +100
6 -50 7 -90
5 -100 8 -120
4 -150 9 -150

Simulation Details

A bidding program (the Senorita) and the Gib double-dummy solver are used for simulations.  There are three types of auctions to consider in a simulation:

  1. A North-South auction without competition.  This bidding accurately represents real world bidding.
  2. An East-West auction without competition.  DONT and Woolsey follow Cohen and Robinson rules to find a strain quite accurately.  There are cases where overcaller proposes one or two suits, and advancer wants a different suit, and I continue to fine tune these auctions.  If West overcalls, the bidding continues to find the systemic East-West strain.  Several defensive bidding systems are used.  If West and North pass and East bids, then East-West bid to their strain.  If West passes and North bids, then East-West stay out.  (Some defenses use business doubles.  I do not know the follow-ups.  The requirement for a double is set high to avoid most doubles.) 
  3. Real world auction where both sides bid.  North-South's may:

Competitive auctions are less likely when fourth seat balances, and so that is the problem treated here.  The final contract is most likely the offensive contract or the defensive contract, and not something else.  The motivation should be your best score, and not disturbing the opponents.  Usually you are satisfied with finding your best suit as low as possible, and not worried about further competition, or bidding to game.

Let us get this out of the way now.  One should argue that a computer simulation does not represent the real world, and therefore the results need to be interpreted.

I think these factors favor bidding with distributional hands.  You have to guess at what declarer's advantage is at 1NT when fourth seat has various patterns.  I am sure it increases as fourth seat goes from a 4-4 pattern to a long suit.

In the simulations, the opener is South and the balancer is East.  I did the problems using several defensive systems.  It suffices to show DONT results.  Unmarked DONT should be read as "East Has Values DONT".  The results for different hand patterns are:

One-on-One Matchpoints (%) vs Vulnerability and Hand Pattern
Pattern Strategy None N-S E-W Both Make% Deals Comments
6 + cards AB DONT 79 57 62 49 67 2256 E-W make 2/3 of the time.  Most of the matchpoint scores are above 50%.  East has "values" over 2/3 of the time.
DONT 74 54 56 48 67 1637

5-5-x-x AB DONT 91 73 75 58 71 2304 With ten cards in two suits, matchpoints and makes are higher.
DONT 88 70 67 52 76 1654

5-4-x-x AB DONT 73 61 55 43 51 2208 Matchpoints and makes are decreasing.  Only half the East hands have "values".
DONT 65 56 52 48 54 1193

4-4-x-x AB DONT 64 53 42 29 37 2592 Even lower matchpoints when you bid with 4-4.  Makes are related to points.  Only 20% of the East hands have "values".
DONT 55 50 49 50 45 487

5-3-3-2 AB 5-3 DONT 65 55 37 23 35 1008 A fictional system.  Makes are below 40%.  Points matter.  Do not bid vulnerable on air.
5-3 DONT 55 49 47 46 38 393

These are numbers for balancing over a 15-17 notrump.  I would expect similar results for other notrump ranges.

Whether or not you make with a 6 + card suit seems unrelated to point count.  If West has the points, East wins trump tricks to take successful finesses through South.  If East has points, the average points per deal is probably higher, but the finesses won't work.

These experiments suggested an optimized DONT, an optimized Brozel, and an optimized Woolsey.  The optimization corresponds to that suggested in the first table in this chapter, and is not intended to produce the best simulation score.

The table below has the results of a 2304-deal pair game where one East-West pair passes, and the other pairs play 4-4 DONT, 4-5 DONT, Woolsey, Brozel, Hamilton, and Always Balance and optimized versions of everything but Hamilton.  Each match is also scored at IMPs, and IMP results agree with matchpoint results.  This table will be rebuilt with minor changes to the optimized systems. 

East-West Pass-out Matchpoints (Percent) vs Vulnerability
Rank System None N-S E-W Both Average
1 Opt DONT 58.08 51.36 51.86 50.31 52.90
2 Opt Brozel 55.00 51.76 51.90 49.61 52.07
3 Opt Woolsey 53.59 51.45 52.14 49.61 51.70
4 AB 4-5 DONT 51.60 51.32 52.06 50.41 51.35
5 AB Wool 53.59 51.45 52.14 47.60 51.20
6 AB Brozel 54.90 51.65 51.81 45.21 50.89
7 AB 4-4 DONT 58.08 51.35 49.05 40.90 49.84
8 5-3 DONT 47.14 49.57 49.25 51.94 49.48
9 4-5 DONT 47.14 49.48 49.25 51.85 49.43
10 Brozel 47.78 49.21 48.99 51.64 49.40
11 4-4 DONT 47.88 48.43 49.41 51.48 49.30
12 Woolsey 46.71 48.29 48.91 51.66 48.89
13 Hamilton 46.66 48.38 48.51 51.83 48.85
14 E-W Pass 31.84 46.29 44.72 55.96 44.70
Deals 576 576 576 576 2304

To be precise, second seat plays 4-4 DONT, and fourth seat plays the indicated system.  Pairs are ranked according to their score averaged over the four vulnerabilities.  Pass is the big loser with no one vulnerable or one of the pairs vulnerable.  Pass  is best with both vulnerable, because Gib finds the double-dummy defense.  I still favor one of the optimized systems with both vulnerable.

If you compare the pair-game, not vulnerable Opt DONT with E-W pass, you find 58.08% and 31.84%.  These numbers are watered by many other pairs doing the same thing on the boards.  In a not vulnerable, one-on-one comparison, the numbers are 75% for Opt DONT and 25% for E-W pass.

The requirements for a second seat overcall are light.  Second seat has, in the longest suit, 12 suit points not vulnerable and 15 suit points vulnerable.  The first hand in the next section is four points light for a not vulnerable overcall.
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