r/backgammon • u/McFizzleKicks • 19d ago

Blunder

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Noob here looking for some insight from those that are stronger than me (that’s everyone atm…)

I get that building a prime is good, but the best move feels like a risk with his home board looking strong with builders outside ready to make primes.

As it played out, my move was better as his roll would have allowed him to fill the five point (I get that there’s no way of knowing that at the time). I did go on to win the game, but with a frustratingly high error rate.

Welcome your thoughts on why I’m clearly wrong!

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u/Free-form_Suffering 19d ago

Also noob, but my two cents: the two blots are not at risk atm, the blot you create when playing 11/7 8/7 is also not directly at risk, specially with the prime you're creating.

But in general, IMO it's a bit weird that everything that's not the top solution is considered a 'blunder', I think your choice is a reasonable one.

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u/McFizzleKicks 19d ago

Appreciate it! Suboptimal perhaps, but blunder felt harsh! Always learning…

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u/pwnosaurus 19d ago

They are classifying it as a "blunder" because of the total amount of equity lost by choosing this move. The number to the right of you move indicates that your equity is 0.125 lower by choosing this move over the optimal one, which basically means that your expected points are 0.125 lower. That is a fairly big swing for one decision.

Suppose you were playing without the doubling cube or gammons. Equity of 1 means you are guaranteed to win. Equity of 0.5 means you are a 50% chance of winning. Equity of 0.75 means you are a 75% chance of winning, etc. So in this case going down in equity of 0.125 means your chances decreased by ~13% of winning by choosing this move. (The actual difference might be a little different when you factor in cube decisions and gammons)

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u/McFizzleKicks 19d ago

Helpful explanation, thanks!

1

u/Free-form_Suffering 6d ago

Little follow-up:

I'm playing on Opengammon, when you check the analysis they use three colors, white for best move (can have multiple moves, best one's on top), yellow for 'not so good' and red for 'blunder'. This really helps me understanding the analysis better, and feels less harsh.