Spoiler alert – if you haven’t read Position of the Week 1 already, you might wish to go back and see that before reading to the bottom of this post!
Graham Davidson writes:
I am a member of a small backgammon club in Sydney. I recently posted a problem which I thought was pretty interesting – but didn’t get much feedback 😊 Now it could be that it is too flaming simple for the typical backgammoner mind, lol – or it could be that I posted the answer after XG analysis, and no-one wanted to add to that.
I call this “Greed or Caution”. Basically you are almost certain to win, but are given the chance of a hit, with a small risk of losing, but with a massive increase in chance of a gammon.One thing I know for certain is that I hit, and then so did my opponent – with a 63 – however I thought it was interesting that I STILL had a 76% chance of recovering and beating him across the line. Didn’t happen. I went on to lose.
Over to you, then!
Answers
Again the consensus gets it right! eXtremeGammon says:
This one isn’t even close. If you leave the blot alone, yes, you are gin, but with seven crossovers to get off and Black having seven to save the gammon, you only get that gammon 22% of the time. Hitting raises that to a comfortable 61.7% – and what does Black have to do to win? Hit you now with 63 or 54, or sit on your acepoint and hope for a shot as you carry on bearing off – and even then, hold that man in long enough to make up the deficit. With each extra gammon worth half of an extra loss, Black would need to be nearly 20% to win to make you play safe; in reality he’s barely 5%.
I think future bot analysis should be presented under the POTW# itself not under POTW#+1.
This POTW has already been ruined because of that…
Anyway the logical thinking for POTW 2, is that if blue was aiming at a Single pt win he should have cashed it via D/P before even rolling. The reason he didn’t do that was because it was TG to double. In fact it is even more Too Good now with the hit. Therefore 19/13* is trivial.
Point taken, if you read 2 before 1 then yes, you could see the answer to 1 before the question. I hoped the warning at the top might be enough. Starting with #3 I’ll do that, and revise this one in due course. The downside of answers after the article itself, though, is that you need to remember to go back and re-read old articles.
It would be wrong to assume, though, that moves and cube actions prior to the diagram were correct, as they have arisen in normal play. The bots might not have got here themselves, but then they must miss out on some interesting positions…
The graphic looks like you rolled out the hitting play but analysed the non-hitting play on 4-ply?!?
I don’t understand one thing. Was this a money game, and so, why was the cube in the midlle?
I guess you are correct for the geeks like me interested in backgammon problems its quite obvious to go for the gammon. In fact there is no risk whatsoever because even when hit back you could double out.
However this doesn’t mean that the position is without interest esp to the beginner and improver , it is yet another reminder that in backgammon the aggressive play is right more often than the passive but its understanding when to be aggressive and when cautious that makes you a top player.
As for POTW#2, for your opponent to win that game (to state the obvious), he has to hit with a 63 or a 54, (4 rolls in 36, or 11.1%) – followed by going on to win despite only a 24% chance (product = 2.67%). Hence effectively, he has slightly less chance than he has of rolling a particular double (1 in 36 or 2.78%). Unthinkable yes (?0 lol. Remonds me of that dad joke, How do you think the unthinkable? – Answer = with an ithberg 🙂
Thanks Julia (etal) for interpreting that situation and the associated table so succinctly, lol – Please note that 3-away refers to BLUE (not black), irrespective of what the spreadsheet table says 🙂 And as you say, if blue was 2 away, (irrespective of whether black was 7-away, 6-away, 5-away or 4 -away), then you should zip rather than hit. PS As for why 4-away is a significant blunder to hit whereas the others are only a misdemeanor / error, it could be that you should try to avoid being gammoned if you are 4-away. But , but, lol – wouldn’t that also apply if you were 3 away? (So much to learn, only 24 hours a day to learn it 🙂 )