Newsletter for 20 January 2004

Martin Luther King Jr. Edition

On Tuesday, 20 January 2004, the Backgammon Club of San Diego met, and it's safe to say that the days of a dead club are past. It's not the local hot spot yet, but at this point you can rest assured that if you show up, there will be a tournament!

Tournament News

Six people entered an 8-player bracket on Tuesday night, with the following results:

First place: Bruce Haight
Second place: Jason Lee
Third place: Adrian Costa & Marcia Karen (split)

Once again, several matches were played using clocks. The club has a digital clock, and Jason brings his own digital clock. Club rules say that the tournament director has the authority to mandate that any particular match be played with a clock -- and can even impose the use of a clock on matches already in progress, but which started without a clock.

Current Master Points Standings

With his win in the tournament, Bruce moves into a tie with Marcia for the early lead in the Master Points race:


Bruce Haight      9
Marcia Karen      9
Jason Lee         8
Sho Sengoku       8
Adrian Costa      6
Fred Kamgar       1
Sam Mehri (?)     1

Remember that the point leader at the end of the year will be named the BCSD Player of the Year, and the top 16 in the Point Race will be invited to the 2004 BCSD Tournament of Champions, to be held in early 2005.

Problem of the Week

Here's a nice one from a late chouette that created some interesting action. At the table, Black (in the box) held three 2-cubes, and redoubled all. Two people took, and the bold soul sitting in the leather Captain's seat beavered to 8, which was accepted.

+-13-14-15-16-17-18-+---+-19-20-21-22-23-24-+

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+-12-11-10--9--8--7-+---+--6--5--4--3--2--1-+

Money game. Black on roll. Cube action? Pip counts: White 57, Black 154

Did anybody do the right thing?

Last Week's Problem of the Week

Last week we considered a position that came up in a semifinal match after an ace-point back game.

+-13-14-15-16-17-18-+---+-19-20-21-22-23-24-+

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+-12-11-10--9--8--7-+---+--6--5--4--3--2--1-+

Black leads 2-0 in a 7-point match. Black on roll. Cube action? Pip counts: White 29, Black 30

What to do? Let's check rolls, and see how many checkers can be borne off, and how many leave shots. We presume that Black wants to play safely. 10 rolls leave a shot: 1-2, 1-4, 2-6, 3-4, 4-6, and furthermore, White will be shooting at no worse than a 3-point board. If Black should leave a shot, White cannot sit around anymore... he's simply got to rewhip it to 8, and Black is going to have a tough time taking, since a hit likely wins the game -- and that's not the only way White can win the game.

Add that up, and it appears to be a take for White. The preceding analysis seems to show that it's probably a take for money, so at this match score it must be a no-brainer.

Is it right to double? Turn everything around, and it seems doubtful. Same logic in reverse -- Black fears that recube to 8, and should sit on it a roll... the entire situation is governed by that rewhip threat.

Here's the results of a rollout by Gnu:

Cube decision

Rollout cubeless equity +0.295 (Money: +0.295)

Cubeful equities:

1. No double +0.482

2. Double, pass +1.000 +0.518

3. Double, take +0.033 -0.449

Proper cube action: No redouble, take (46.4%)

Rollout details

Win W g W bg Lose L g L bg Cubeless Cubeful

Player Black owns 2-cube 0.648 0.000 0.000 - 0.352 0.000 0.000 +0.295 +0.482

Standard error 0.000 0.000 0.000 - 0.000 0.000 0.000 0.001 0.002

Player White owns 4-cube 0.648 0.000 0.000 - 0.352 0.000 0.000 +0.611 +0.033

Standard error 0.000 0.000 0.000 - 0.000 0.000 0.000 0.002 0.003

Truncated cubeful rollout (depth 11) with var.redn.

7776 games, Mersenne Twister dice gen. with seed 958726464 and quasi-random dice

Play: 0-ply cubeful [expert]

Cube: 2-ply cubeful 100% speed [world class]

See you next week! Keep tossing those cubes,
J. Lee

Output generated by GNU Backgammon 0.14-devel (HTML Export version 1.123)