Two sequential positions from the same game.

Match to 7, white is leading 5-4. Centred Cube.

First position: Red to play 51



Second Position: Red to play 53



In both positions, anything other than switching with 6/1 is a blunder, but I don't understand why. Doesn't breaking the 6pt just make it easier for white to escape?

Also, what is red's main objective in these situations? Perhaps a clearer understanding of the theme for the positions would help me...

Thanks.

Escaping for White shouldn't be too hard anyway since he has the 3-pt anchor and you won't maintain your 5-prime (or broken 5-prime in the 2nd case) for very long unless you roll a 6 now.

In both positions, you don't want to bury checkers on the 2-pt behind White's anchor. By switching points, you hope White won't roll a 6 from the bar (or 3-3) and hope you can cover the 6-pt with a 1 or a 2 next roll (only a 2 for diagram 2) or hit with a 6 and safety the blot on your 6-pt if you can't cover it.

I think the main consideration here is that getting hit is a disaster no matter if it happens on the 6-point or the ace. The only thing that matters is how likely you are to safety the blot after red misses. Also, GNUs play does not duplicate your sixes.

Edit:
yeah, this is basically what uberkuber said already...

So "safety" rather than "containment" is the theme here... thanks, that was the insight I was missing.

I guess 6/1 makes sense as the safe play in position 1, since I'm left with 2 builders to cover either with 6/1 or 7/2 (given that any 6 will be used to hop white's prime rather than cover), and 7/2 creates an extra outfield blot, which obviously gives up more gammons when white hits from the bar.

But how is 6/1 the safe play in position 2, when 7/2 cleans up the blot on the 7 pt, AND leaves me with 2 covering numbers for the ace point blot (4 & 1), rather than 1 covering number for the 6pt blot (2)? The only down-side I see is burying another checker, but as I'm 40pts ahead in position 2, why does that matter, compared to the safety of having another covering number?

Is crunching much of a consideration here? Obviously leaving a man on the 7pt lets me handle one more awkward 5 in the future before I get the 6 I so desperately need...

If you play 7/2 5/2, you don't have the 4 anymore to cover your 1-pt.

If you play 7/2 8/5, you lose the useful 8-pt as a blocking point against White's 3-pt anchor. Plus, if you get hit on the 1-pt and White scoops your blot on the 8-pt, you then become a big underdog.

ah, gotcha, thanks. my post-move visualization skills clearly need to imporve

thanks for breaking this down for me.