the dorbel daily

Monday 12 March 2012

Learning To Love The Cube part 5

So, with all this talk of aggressive doubling, I expect that you want to see some examples. They aren't hard to come by. Almost every match has a crop of them. Clearly the most potent are those that have a large gammon component, gammons for you when successful and lots of wrong passes when Gammon Fear strikes at the heart of your opponent.

Game One, 0-0 to 7, Black on roll and White on the bar.

Forty pips up and with White on the bar, it's pretty clear that Black has a double, but can White take? Well, she is anchored, she doesn't have any more blots hanging about and there are plenty of Black rolls that don't cover both blots. 6-6 and 6-5 don't cover either! Even when Black can cover both, White is still a favourite to enter and often has some indirects to spice it up a bit. Cubeless, Black is going to win 66% from here with 27 gammons, but White's cube ownership is enough to give her a comfortable take. A pass is a blunder, but White passed.
A hidden plus point for Black when he gets a pass here is that it's a big tell for future games. Information about how White handles dangerous cubes is very valuable indeed. So, in game Two, now leading 1-0, I reached this next position and turned the cube.

You can see straight away that Black is nothing like so strong here. He only leads by 11 pips, 142-153, White isn't on the bar and Black's hitting fives are duped. White also has the stronger board, but that is cancelled out by havingtwo checkers out of play, so the positional variants won't be so easy to play for her. However, I doubled and White took. The double is an error costing about 0.057 technically speaking, but 11% wrong passes is enough to make it correct. Does White pass this that often? Probably not, but anyway, I've doubled her into a game where I win 65% of the time with 22% gammons, so not so bad! A long game saw me get hit and closed out after bearing off 8 checkers and eventually we got down to this next position, where White finally gets a chance to use a 4 cube.

This is exactly what I have been talking about when I say that a lot of equity for the taker lies in her ability to use a 4 cube correctly. This one isn't hard to work out. White wins 1/6th of the games straight away with a doublet and when she only rolls a singleton Black has 19/36 misses. 1/6 + 5/6 x 19/36 equals 131/216 or a shade over 60%. Tragically White failed to cube, a 0.194 blunder. This pays for my initial cube error three times over!

I'll leave you with this nice position to think about. Black is on roll, White is on the bar and it's 0-0 to 3. What's the correct cube action for both sides?

Let me have your thoughts please and we'll come back to this in the next post.

There's a good match on Fibs tonight (Monday) at 1900 UTC, stukatz (USA) plays BushSucks (Germany) in an 11 pointer, the semi-finals of Fibsleague 55 play-off. These are both experts so it should be a good battle. Whisper only please watchers.

A reminder that entries close for Escoffery's Fibs Spring Open on March 25th, so don't delay, get an entry in today. for all the rules, contact address etc.
Until we meet again, enjoy the game!

1 comment:

ah_clem said...

OTB, I'd take a shake and see what happens - there's lots of gammons afoot and few sequences turn the tables. A rule of thumb is that if you can't lose on the next sequence, it's correct to play on for gammon no matter how small the chances.

From White's perspective, she'll probably breath a sigh of relief to get out of this pickle only down one point. So I'm going to say ND(TG)/P

That said, I don't think it's a huge error to cash, and if White erroneously takes, more the better.