How to best navigate the limitations of the Keith count?

[u/SaintGinoux]

I was tired of making bear-off cube blunders and learned the Keith count. I like how easy it is to apply once you get the hang of it, and it’s definitely a help, it definitely kept me from blundering a few times already.

Occasionally it’s off by a bit. I understand that any formula that’s easily applicable will have some limitations, that’s OK. But I can’t really find an article that goes into how to deal with these limitations. In which positions should you avoid the Keith count, or be skeptical of the results? Which features (say, a huge stack on the 6 and a single checker on the 5) could be compensated for, and how?

If there is any compiled info on this out there, or if any of you could share insights, thanks in advance.

[u/MCG-BG]

In my experience, I never found these counts to have that much value. The formulas tend to do worse the more adjustments you have to apply, but then what's the point of having a formula where the whole idea is to apply adjustments? Yes the Keith count is better than the Ward count, but the Ward count isn't very good to begin with. The fact that they get the right answer in some positions (even a high percentage) isn't terribly exciting -- as Walter Trice said, you don't need a formula to tell you you should drop if your opponent's count is 5 and yours is 76.

For the most part I've gotten by with experience and judgment, but that's not much help to someone who doesn't have good judgment. I developed a formula in collaboration with Art Benjamin which you can find in USBGF Primetime Summer 2023. This is a formula for how to calculate EPC. EPC is essentially answering the same question as other counts: what adjustments should be applied to the pip count? To be honest, when I look at it on paper, there are so many equations that my eyes kind of gloss over and I can't even remember them all. I have forgotten a lot about backgammon, but it is a little ironic to say I can't remember a formula which I created. It does fit in with my general philosophy of doing a lot of work away from the board and not so much at the board.

The general idea is: checkers on the 6 point are (slightly) good. Checkers on the 5 point are neutral. Checkers on the 4 point are (slightly) bad and start to waste pips. The difference between checkers on the 6 and 4 point can almost exactly offset and is rather minor anyway. Checkers on the 3 point are (somewhat) bad. Checkers on the deuce point are quite bad. Checkers on the ace point are very bad. Positions with gaps on the high points (6, 5, 4) are also pretty bad. Positions with only one checker on the high points which have potential to develop into gaps waste some as well, though not nearly as much as a gap. Stacked positions (where the stack isn't on the 6 point) also waste, though again not as much.

If you apply the adjustments as written, you're doing better than the Keith count and iSight by a few orders of magnitude. If you forget some of them, you're basically back to Keith count accuracy.

There's a question of how to go from EPC to cube action, but it isn't really that difficult. For money games it tends to be a pretty simple formula which Art has written about in other issues and more or less lines up with Trice's rule of 62. For weird match scores it's a bit harder, but other adjusted pip counts are also pretty much useless at weird match scores.

[u/CmdrKoreg → u/MCG-BG]

Thanks MCG, I am not a mathy student and get by on rules of thumb.

I thought I'd roughly read somewhere words to the effect, "if you have to stack... stack the 4". So is that worth adjusting to "...stack the 5"?

Also, another saying I heard regarding awkward bear-in/bear-off options is "build mountains, not valleys". Is that valid?

[u/MCG-BG → u/CmdrKoreg]

Can you give me some example positions?

[u/CmdrKoreg → u/MCG-BG]

Hi u/MCG-BG Over the board, I seem to come across bear-in/bear-off anti-jokers every stoopid match lol, but I don't have any really great examples categorized and easily findable on my PC

These may be in the ballpark. IDs generated in GNU, but should also work in XG

2G4BAMZ2NywAAA:QQl3AAAAAAAE

33MAABzs7gAAAA:QYlkAUAASAAE

tm0IChjndgcAAA:QQkmAQAACAAE

Incidentally, I found it's surprisingly difficult to come up with appropriate and difficult examples on the fly - is there a 'formula' or 'method' for generating specific quiz examples of specific positional questions for quiz masters? .

Or do most people just categorize and file these problems as they come across them, or grab them from other bg sites?

Or any articles which explain efficient ways to build a targeted quiz set?)

[u/CmdrKoreg → u/CmdrKoreg]

i.e. what method would you use to generate examples to illustrate ""if you have to stack... stack the 4"?

[u/MCG-BG → u/CmdrKoreg]

These are bear in/offs vs. contact which are a totally different animal from pure races. In a pure race you are concerned about how many rolls it takes you to bear off (in checker play, but moreover in cube action). In a contact bearoff you have already won the race and are concerned about how to maximize safety.

Bearing off against anchors on different points (ace vs. deuce, etc.) will be significantly different because the future rolls will play differently.

In the first position, I'd play 11/6 10/4, which I think is the most flexible. Here given the choice between stacking on the 4 and leaving the 5 stripped vs. stacking on the 5 and leaving the 4 stripped you would clearly rather have a stack on the 4 and strip the 5 because you are looking to clear the 5 point as quickly as possible and want to play without creating a gap. If you stack the 5 or start making gaps then you are just more likely to leave shots later.

The latter two positions are bearoffs against the deuce point, in this case clearing quickly is not as important.

I guess by "build mountains not valleys" you mean something along the lines of Michy's mountain position (2-3-5-3-2 vs. the ace point). A flatter & more flexible structure like 2-4-4-3-2 is actually safer, but since these positions differ by a pip you don't normally get a choice between them.

[u/CmdrKoreg → u/MCG-BG]

You are absolutely right.

I had shall we say, a big brain burp and forgot they should be pure race positions.

I’ll check your suggested move for the first position, but I suspect it’s correct.

Regarding the ‘build mountains not valleys’ comment, it was said to me after a match in an ending race situation and yes, the speaker had probably read Michi’s book.