White is leading 5:2 in a 7 point match. Green doubled. White rejected which was a huge blunder.

I understand the reason why this was a blunder: White already had 7 checkers outside.

What I don't understand:

(1)

GNUBG says White has a winning chance of only 0.227 so less than 0.25. As White is leading in the score I thought it would need more than 0.25 to accept?

(2)

According to https://bkgm.com/articles/mpd.html the market window for player 2-away and opponent 5-away is 30-81. I thought this means that the player (White) can accept when his winning chances are more than 30% which isn't the case here.

Can somebody explain this?

In non-gammonish positions when your opponent is 5-away, you can take a little deeper than usual. This is because when you pass, your opponent gets to 4-away which is a comfortable score to be at, the cube is very useful at that score.

I think 30-81 means the doubling window closes at 81% so you can take at 19%? Or maybe you should be looking at 5-away 2-away when you are looking at 2-away 5-away? I don't know, the chart seems confusing. In any case, XG uses a different match equity table than that link.

You might find my posts in this thread interesting:

https://forumserver.twoplustwo.com/1...51/?highlight=

Is there a table at which score you need which winning percentage to accept? (I thought the one in my link would be that but probably I misunderstood it.)

When you google for that you often find match equity tables and you mention them too. But I don't find them practical because you need to make a calculation to come to the required winning percentages. As I often lose matches because of lack of time I would rather need a table that displays those percentages directly without calculation necessary.

Looking again at the chart, I think it does do what you are looking for. It's saying the take point is 19% for your example. But it's using an old match equity table to do the calculations. I have not seen other tables that just list the take points.

For the scores where the cube is dead after doubling (including any automatic redoubles), it's helpful to memorize the take point for common scores in 5 or 7 point matches. When the cube isn't dead, knowing what the raw take point is isn't that useful because it ignores too much. For 3-away 3-away, if you calculate the take point, it'll be something really high, like 30+% but that ignores the fact that the taker has very good recube leverage which brings down the take point a lot. Plus there's gammons to worry about. So I tend to think more qualitatively in those situations.

I would like to use that table qualitatively. Besides all other factors like gammons etc. it would tell me which scores rather are for accepting and which rather are for rejecting when it's a borderline case. Because I would have thought that a lead of 5:2 is rather for rejecting while it obviously is rather for accepting.

So that match equity table is outdated? Can you recommend a link with one that is up-to-date?

The Kazaross-XG2 Match Equity Table is the current gold standard.


https://bkgm.com/articles/Keith/Kaza...MET/index.html

Thank you!