Hello!




In both positions Black doubled and I gave the wrong answer. I normally use the "PRAT" system for such decisions but it misleads me far too often. Does anyone know a more sophisticated approach to handle such take decisions?

I'd say 1) take 2) pass at first glance but far from sure.

Seems very clear to me to take in position 1 and pretty clear to pass in position 2.

I sometimes think of PRAT as a way to start thinking about a position, but tend not to use it, because it ignores how much a positional edge is worth and how much a race lead is worth and how strong the threats are. So that’s sort of the whole ballgame.

I don’t have great advice for how to analyze these because it’s hard. Memorizing reference positions can help, but unless you have a fairly close position in mind you might not have anything useful. So all you can do sometimes is go through the relevant factors like board strength, number of men back/on the roof, etc. and then take an educated guess. The more you do it and see the computer analysis, the better your guesses will get.

I like to specifically ask “how can I plausibly win this game”? In the first position even if your blot gets hit you will probably anchor immediately (on your slotted 20, 23, the 24, or multiple points) while your opponent only has one offensive point made and 2 checkers back, which has to give you at least 30-40% winning chances (if not more).

In the second position we just don’t have a plausible route to winning the game. Usually our opponent will have cleaned up those blots before we enter, then from there we’re basically hoping to make and sit on the 23 pt then hit a shot to win (since we never win a straight race). But with a 23 pt anchor game we need basically perfect offensive structure or major weaknesses in the opponent’s structure to be able to take a cube, and here we haven’t built anything yet so we need to drop.

So at the end of your thought process one brain cell says "clear". But what are the steps in your brain before that? What are the upsides and downsides you consider? How do you decide which of them is stronger? Not only headlines please but the details that lead to the result "clear".

Interesting, sdfsgf, thank you!

PRAT actually works reasonably well with these positions. In both black has a race and positional advantage, so it comes down to threats. In position 1 black does not have any serious threats. The biggest threat is that he will hit the blot in whites home board, but that does not particularly hurt white’s chances. White already is behind in the race and already has three checkers sent back. A fourth checker sent back is not too damaging and likely will result in an anchor that will stop black’s attack. Black is not going to be too eager to hit white’s checkers deep in his board. He might hit loose on his 5 point, but that will leave return shots for white and give white a decent chance to even the position out a bit.

By contrast the second position black has threats. Making the two point on whites blot iota two in the air Bs a three point board, and black has lots of ammo to press the attack. Even if black cannot attack, he likely could clean up his blots and look to attack or prime. These are real threats, so PRAT would tell us to pass.

Just a rule of thumb for position 1 that I’ve heard - Don’t be too eager to drop a double when your opponent has a checker on the bar. That half roll used to enter often prevents him from carrying out threats.

Hmmm, I would have said that in position 1 Black has an overwhelming armada of threats with hits and double hits all over the place whereas in position 2 Black has not and rather White hopes to have a threat because maybe the 18 and the 15 blot can't be saved both.

So maybe the problem is that I have a wrong understanding of "threat". Can you recommend a page where the PRAT concepts are explained in more detail so that I can eliminate such misunderstandings?

I must admit that I don't understand your second paragraph: "iota two in the air Bs" ???

You’re right that Black doesn’t have many immediate/crushing threats in the second position. That’s why (even though it’s a big pass, by 0.240) it’s only a small error to not double now (by 0.063) — it’s not that much worse to wait a roll then probably double the next roll because the position usually isn’t going to change that much. But even though the volatility isn’t that high, White still has to pass because the winning chances just aren’t there.

Sorry don’t know how that got garbled. Should read “puts two in the air vs. a three point board.”

As far as threats, it is important to realize that threat does not always mean hitting blots, and potentially having blots hit is not always a threat. A threat is really just a move that would significantly decrease your equity if your opponent carries it out. In position 1, even if black hits twice, white still has two blots in blackÂ’s home board. This makes white a favorite to make an anchor, which would stop blackÂ’s blitz and give white reasonable winning chances for the remainder of the game. Black in this position also still has two back checkers. After anchoring white can hit loose fairly aggressively and attempt to attack or prime these stragglers.

In position 2 on the other hand, black has threats that are much more significant. Besides the obvious - making the 2 point with either 64 or 44 (which would also allow black to make the 4 point and would be devastating for white), black has additional threats. 66 would give him a five prime. 52 allows him to either make the 4 point or safety both back checkers. 22 would give him the 4 point plus a broken 5 prime. Any 5 or 2 allow him to clean up one blot. Any three allows him to safety both blots. The lack of back checkers for white to attack or prime is another critical feature. Even if white anchors and survives the blitz, he may still not have much chance of winning.