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[Event "Nashua Fri 2:15 6-22-2018 -- Problem"]
[Site ""]
[Date ""]
[Board "4"]
[West ""]
[North "Gary"]
[East ""]
[South "Pete"]
[Dealer "W"]
[Vulnerable "All"]
[Deal "W:QT2.AJT96.3.JT97 753.K54.J542.Q43 KJ84.Q2.A986.AK2 A96.873.KQT7.865"]
[Scoring ""]
[Declarer ""]
[Contract ""]
[Result ""]
{


Playing matchpoint pairs, suppose you decide to lead a diamond.  Which one do
you choose?

There are three reasonable choices with standard leads:

\DK -- partner will give an attitude signal, hanging onto the ace or jack, if
he has it.  Partner would surely signal encouragement holding the \DQ.  You
know he does not have it, but he might have the ace.  Partner's most likely
useful card is the \DJ.  Since you might be leading the \DK from AK or KQ,
partner might well discourage when holding the jack.  Whatever you do next will
be a guess.

\DQ -- partner will play the \DJ, if he has it without the ace.  If partner
does not have the jack, you will know for sure who does.  This standard
defensive agreement protects you against a <i>Bath Coup</i>, the case where declarer
ducks from \DAJx.  Knowing where the jack is prevents you from falling into
declarer's trap.

\D7 -- This one wins in most cases when partner has four or fewer diamonds
including the ace or jack.  However, if partner has five diamonds headed by the
jack, you will have blocked the suit (unless pard applies the rule of eleven,
has the nine, and plays it).}
[BCFlags "1f"]
[Hidden "NEW"]
[Auction "W"]
Pass Pass 1NT =1= Pass
2D =2= Pass 2H Pass
2NT Pass 3NT AP
[Note "1:15-17 HCP"]
[Note "2:Transfer to \H"]

[Event "Nashua Fri 2:15 6-22-2018 -- Solution"]
[Site ""]
[Date ""]
[Board "4"]
[West ""]
[North "Gary"]
[East ""]
[South "Pete"]
[Dealer "W"]
[Vulnerable "All"]
[Deal "W:QT2.AJT96.3.JT97 753.K54.J542.Q43 KJ84.Q2.A986.AK2 A96.873.KQT7.865"]
[Scoring ""]
[Declarer ""]
[Contract ""]
[Result ""]
{

My choice was the \DQ.  Partner duly deposited the jack on the opening lead,
and we could no longer set the contract.  We took only two diamonds to go with
our heart and spade winners.  My lead was successful, in that I resolved the
issue of the Bath Coup.  A successful play that loses the board is quite
disappointing.

Nevertheless, at matchpoints, where every trick counts, a leading a diamond
honor is appropriate.  Leading the \DK would have preserved partner's jack.  We
would then have to guess at the next trick, having had a look at dummy.  The
\DQ works on this hand, with this agreement, played by some:  when an
unexpected singleton or void appears in dummy, partner signals encouragement
holding the jack.

At IMP scoring, the correct lead could well be the \D7.  If partner has the
\DA, we set the contract immediately.  If he has the \DJ, we establish three
diamond tricks -- if pard has another trick, we again set the contract.  (Don't
call me, if \DJx comes down in dummy.)  The \D7 could be a top-or-bottom lead
at matchpoints, especially if partner has either a doubleton honor or no honor.

From KQT9(x) or KQTxxx, the Q should usually be led against a notrump contract
at any form of scoring.  From KQxx(x) or KQTx, it is normal to lead low playing
IMPs, but to lead the K at matchpoints.  From KQTxx, consider the auction. 
With no reason to expect an opponent to have four cards in the suit, the lead
of the Q can be quite effective.  However, if you intend to attack a suit bid
by an opponent, or where an opponent likely has four cards, leading small gives
the best chance of running the suit.  Diagnosing a Bath Coup becomes secondary.
 While declarer has not bid diamonds on this deal, we can expect declarer to
hold four diamonds roughly half the time, with the likely doubleton heart.

Using \SA6 \H873 \DKQT72 \C865 for the South hand, I had GiB play 200 deals
with the lead of the \DK and the \D7.  Declarer took a total of 1963 tricks
against the \D7, achieving a better result on 112 deals, going down 37 times. 
Declarer took 1803 tricks against the \DK, better on 35 deals, and going down
64 times.  Declarer took 0.8 more tricks per deal, won the board more than 3
times as often, and went down far less often against the \D7.  GiB definitely
does not understand the conventional \DQ lead, which produced similar, but
slightly worse results for the defense.}
[BCFlags "1f"]
[DoubleDummyTricks "42252422528bb8b8bb8b"]
[OptimumScore "EW 650"]
[Auction "W"]
Pass Pass 1NT =1= Pass
2D =2= Pass 2H Pass
2NT Pass 3NT AP
[Note "1:15-17 HCP"]
[Note "2:Transfer to \H"]
[OptimumResultTable "Declarer;Denomination\2R;Result\2R"]
N NT  4
N  S  2
N  H  2
N  D  5
N  C  2
S NT  4
S  S  2
S  H  2
S  D  5
S  C  2
E NT  8
E  S 11
E  H 11
E  D  8
E  C 11
W NT  8
W  S 11
W  H 11
W  D  8
W  C 11

[Event "Nashua Sat 10am KO 2018-06-23 -- Problem"]
[Site ""]
[Date ""]
[Board "31"]
[West "Gary Schwartz"]
[North "Doug Doub"]
[East "Pete Matthews Jr"]
[South "Yiji Starr"]
[Dealer "S"]
[Vulnerable "NS"]
[Deal "S:J74.KT6.J872.A53 AT2.J8742.K9.976 963.Q3.T64.KJT42 KQ85.A95.AQ53.Q8"]
[Scoring ""]
[Declarer "E"]
[Contract "4H"]
[Result ""]
{

Whether playing the 1NT opening as 15 to 17, or our half-point stronger
version, unless West decides to pass 2\H, this will be the action at many
tables.

With four obvious losers (two hearts and two clubs), plan the play as East, on
the lead of the \D2.

On its own, there is a legitimate play to lose only one trump.  For it to work,
you need South to hold any two hearts, including the ten.  The play is an
<i>intrafinesse:</i> lead the \H5 toward dummy; South must play the other trump
(not the 10).  Whether South or North wins this trick, at your next chance, you
lead the \HJ from dummy, pinning the ten in the South hand.  However neat this
is, it probably fails on this hand, as three rounds of clubs will require
declarer to ruff, preventing the second trump finesse.

The alternative is to try to cash six top spade and diamond winners, dumping a
club on the third diamond, and then throw another club on the fourth spade (we
need spades 3-3 for this).  An opponent will ruff; we hope they can only get
one more trump trick.

Is there anything else?}
[BCFlags "1f"]
[Hidden "NS"]
[Score ""]
[Auction "S"]
Pass Pass Pass 1NT =1=
Pass 2D =2= Pass 2H
Pass 2NT Pass 4H
AP
[Note "1:15+ to 18- HCP"]
[Note "2:Transfer to \H"]

[Event "Nashua Sat 10am KO 2018-06-23 -- Solution"]
[Site ""]
[Date ""]
[Board "31"]
[West "Gary Schwartz"]
[North "Doug Doub"]
[East "Pete Matthews Jr"]
[South "Yiji Starr"]
[Dealer "S"]
[Vulnerable "NS"]
[Deal "S:J74.KT6.J872.A53 AT2.J8742.K9.976 963.Q3.T64.KJT42 KQ85.A95.AQ53.Q8"]
[Scoring ""]
[Declarer "E"]
[Contract "4H"]
[Result "9"]
{

Since a successful intrafinesse appeared unlikely to make the contract, I tried
pitching clubs from dummy.  In the process, I cashed the \HA.  North ruffed the
fourth spade with the \HQ, so I could now make the contract by leading a trump
from hand toward dummy.  Unfortunately, I no longer had an entry to hand. 
Dummy was endplayed after ruffing the second club; one down.  

At the time, I remarked that I might have made the contract by retaining the
\HA.  North would then ruff the fourth spade with the \H3.  Doug pointed out
that Yiji could set the contract by winning North's club lead, and producing
her last diamond.  Doug would ruff the \HQ (declarer following), and Yiji would
retain a trump winner.

Another approach would be to start with four rounds of diamonds, pitching two
clubs from dummy.  On a 4-3 split, the defense won't be able to bother us with
a fifth round of the suit.  The defense will likely play two rounds of clubs,
with the second ruffed in dummy.  Cross to hand with a spade, and lead the \H5
for an intrafinesse.  Win a spade or club ruff in dummy, and lead the \HJ, as
planned.  (On this dummy reversal, the fourth spade will not be needed.) 
However, the intrafinesse does not work as the cards lie.

Doug suggested the best play might be a swindle:  win the opening lead with the
\DK, and lead the \H2 to the 9.  If South does not cash the clubs right away,
declarer cashes the \HA, and tries to dispose of two clubs from dummy.  If
spades and diamonds behave, there would be nothing the defense could do, at
that point.

This plays on South's fear of giving declarer an undeserved club winner.  After
all, East could have the \CK instead of the \CQ.

Gary quoted Alfred Sheinwold:  it is not enough to take all your own tricks,
you have to take some of theirs, too.
}
[BCFlags "1f"]
[DoubleDummyTricks "54456544568998789987"]
[OptimumScore "EW 140"]
[Score "EW -50"]
[Auction "S"]
Pass Pass Pass 1NT =1=
Pass 2D =2= Pass 2H
Pass 2NT Pass 4H
AP
[Note "1:15+ to 18- HCP"]
[Note "2:Transfer to \H"]
[OptimumResultTable "Declarer;Denomination\2R;Result\1R"]
N NT 5
N  S 4
N  H 4
N  D 5
N  C 6
S NT 5
S  S 4
S  H 4
S  D 5
S  C 6
E NT 8
E  S 9
E  H 9
E  D 8
E  C 7
W NT 8
W  S 9
W  H 9
W  D 8
W  C 7

[Event "Nashua Tue 10am 6-19-2018"]
[Site ""]
[Date ""]
[Board "8"]
[West "Gary"]
[North ""]
[East "Pete"]
[South ""]
[Dealer "W"]
[Vulnerable "None"]
[Deal "W:.KQ83.AT6.A97542 T7.J7652.Q52.QJ8 KQJ96543.4.94.T3 A82.AT9.KJ873.K6"]
[Scoring ""]
[Declarer "E"]
[Contract "3S"]
[Result "11"]
{

<b><i>Should East invite game with 3\S, or bid 4\S?</i></b>

Using Dealmaster Pro, I generated 5000 deals with the given East hand and
meeting this specification for West:

6+ card \C suit, 0-4 \D, 0-4 \H, 0-2 \S, 12-14 HCP.

Across the 5000 2\C rebids, East can expect an average of 9.19 tricks on the
deal.  4\S makes 38% of the time.  3\S can be made 79% of the time.  Inviting
game is plenty, except you might gamble when Vul at IMPs.

On two past occasions, I have raised partner's invitational jump to game,
holding a void in the suit - partner made game both times.  <b><i>Is this West hand</i></b>
<b><i>good enough to raise 3\S to 4\S?</i></b>

Using Dealmaster Pro, I generated 5000 deals with the given West hand and
meeting any of these three specs for East, all with a maximum of four \C, \D or
\H:

1.  6-card \S suit headed by AK, AQ or any three or more honors, 10-11 HCP
total.\n
2.  7-card \S suit headed by AK, AQ, KQ or any three honors, 7-9 HCP \n
3.  8-card \S suit headed by AK, AQ, KQ or any three honors, 6-8 HCP total.

Across the 5000 3\S invitations, West can expect an average of 8.86 tricks on
the deal.  4\S makes 26% of the time.  3\S can be made 65% of the time, more
than twice as often as 4\S.  Raising to game is clearly folly.

The specs for the simulations are clearly imperfect, but they show clear
answers.

-- Summary of Methods --\n
Double Dummy all deals in two files (2C_REBID = 5000 West hands; 3S_JUMP = 5000
East hands).\n
Using cygwin, create two files containing the number of tricks taken for each
deal in a spade contract by East:\n
grep "E  S" '3S_JUMP.PBN' | tr -d "[a-zA-Z "]" > 3S_JUMP.txt\n
grep "E  S" '2C_REBID.PBN' | tr -d "[a-zA-Z "]" > 2C_REBID.txt\n
Paste both files into columns of an Excel spreadsheet for analysis.}
[BCFlags "1f"]
[Score "EW +200"]
[Auction "W"]
1C Pass 1S Pass
2C Pass 3S AP

[Event "Nashua Wed 10am 2018-06-20"]
[Site ""]
[Date ""]
[Board "23"]
[West "Gary"]
[North ""]
[East "Pete"]
[South ""]
[Dealer "S"]
[Vulnerable "All"]
[Deal "S:J93.AQ752.52.964 AK.9843.KT.AKJ73 Q42.KJ6.QJ.QT852 T8765.T.A987643."]
[Scoring ""]
[Declarer "S"]
[Contract "3D"]
[Result "13"]
{

<b><i>Should East have passed 3\D, or driven to game?</i></b>

Dealmaster Pro generated 5000 deals with the given East hand, and meeting any
of these specs for West:

1.  Balanced hand, 3-3 minors, 19-20 HCP.\n
2.  Balanced hand, more clubs than diamonds, 3 or 4 clubs and 18-20 HCP.\n
3.  Balanced hand, 5 clubs, and 18-19 HCP.

Since our 1NT opening is a good 15 to a bad 18, opener's 2NT rebid is a good 18
to a bad 20.  After bidding 3\C, East can pass 3\D to sign off there, or bid
3\S to play.  With a great hand for spades, opener is allowed to push on, so
3\S is slightly invitational.  There is no way to either invite in diamonds or
offer a choice of games between 3NT and 5\D.  3\D over 2NT would ask about
major suits, but would commit the partnership to game.  We have no agreement on
how to play 5\D, after discovering West has two spades.

After using Bridge Composer to generate double dummy results for all deals, I
extracted these conclusions (using the same methods as for the previous deal):

     Diamonds by West makes an average of 11.01 tricks, making game over 74% of
the time.\n
     Spades by East makes an average of 10.14 tricks, making game over 70% of
the time.\n
     NT by West makes an average of 8.52 tricks, making game over 51% of the
time.\n
     When 4SE goes down, 3NTW makes over 13% of the time (out of all 5000
deals).

Leaping to 5\D is far better than passing 3\D with this 6-loser hand.  The 3\D
major suit inquiry would play 3NT opposite a doubleton, and 4\S opposite three.
 Three spades should improve on the 70% chance at 4\S, while having two spades
improves the chance of running diamonds at 3NT.  The major suit inquiry appears
best.}
[BCFlags "1f"]
[Score "NS +190"]
[Auction "S"]
1C Pass 1S Pass
2NT Pass 3C =1= Pass
3D =2= AP
[Note "1:Wolff: signoff or slam try."]
[Note "2:Required."]
