Later On

A blog written for those whose interests more or less match mine.

Bayesian search techniques for optimal shaving solutions

with 4 comments

When I first learned Go, I couldn’t stop seeing Go positions in the objects around me; now, I can’t stop seeing examples of Bayes’ theorem in action—and let me again recommend McGrayne’s The Theory That Would Not Die.

I just realized that I have based my shave recommendations on a Bayesian foundation, in this sense: I have long recommended—in print—that a beginner’s second razor should be a Slant Bar. (For the first razor, I initially recommended the Merkur Hefty Classic (aka “HD”), but switched to any of the Edwin Jagger DE8x series once that razor was available with the new head design, and that continues to be my recommendation.)

A guy on the Wicked_Edge posted that he started with the Weishi, then tried the Gillette Red-tipped Super Speed, and then a Gillette Slim adjustable. In the course of his description of his razors and their performance, he mentioned that he had a thick, tough beard. That, to me, is Slant Bar bait.

So of course I immediately weighed in to recommend he try a Slant, and wrote:

In my book I stress that the beginner’s second razor should be a Slant Bar (and I recommend one of the Edwin Jagger DE8x series as a first razor).

For much the same reason—gaining experience by trying something different—I would recommend that a beginner’s second brush be of a different sort of bristle than his first: If he began with boar, get a badger; if a badger was first, get a horsehair second; and so on.

I’m reading (with great interest) a book about Bayes’ theorem, so of course I’m now seeing it everywhere, and my recommendation of making a big rather than an incremental change is quite Bayesian and is more likely to lead more quickly to optimal outcomes.

And I realized as I described this to The Wife (who hears, I think she would agree, rather a lot of shaving theories from Yours Truly) that this is a search strategy that quickly gives information on the overall characteristics of the search space by testing widely separated points—for one, a search space of razors; for the other, brushes.

Indeed, now that I have the notion, I can do it better. For razors, for example:

a. Edwin Jagger DE8x
b. Slant Bar
c. Adjustable
d. Straight Razor

Again: the idea is to avoid trying incremental change (i.e., nearby points in the search space) and instead trying a different neighborhood. In fact, I could be persuaded that “c.” should be the Straight Razor.

Written by LeisureGuy

31 October 2011 at 4:23 pm

Posted in Shaving

4 Responses

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  1. While I am interested in eventually trying a straight razor, I would probably put an SE Gem razor at d, “Pils/Modern type” at e and the straight at f. I’ve never read any impressions of yours about straight razor shaving. The biggest thing holding me back from trying it is the stropping. It would be demoralizing to buy a nice startup kit, wait for it to arrive, and then promptly remove its shaving edge by botching the use of the strop. I’ll probably wait until I feel like I’ve plateaued with safety razors. By then, the brush and soap combos will all be perfected.

    Dirty Texan

    1 November 2011 at 6:42 am

  2. Good point. Yes, there is more variety to explore in DE Safety razors. Perhaps the list should be more along these lines:

    a. EJ DE8x
    b. Slant Bar
    c. Open Comb
    d. Adjustable
    e. Schick Injector
    f. GEM G-Bar
    g. Pils type
    h. Asymmetric

    Plus there are the intriguing guys: Apollo Mikron, Eclipse Red Ring, and others… The Rolls Razor anyone? 🙂


    1 November 2011 at 6:47 am

  3. Thanks for the recommendation of what looks like a fascinating book, I just downloaded it to my Kindle.

    On another note: what is Go?



    1 November 2011 at 8:29 am

  4. I’m delighted that you ask. Go is a two-person strategy board game that is about 3000 years old. It originated in China, later moved to Japan, which was for many years the main power. Today it is played worldwide—the Web offers an excellent medium for on-line games—and activity is at a high level. Korean players are particularly strong, it seems, though the Japanese and Chinese are still leaders. There are some links in the sidebar under “Go” and “Games”, and also check out the American Go Association, which has many links. I’m usually playing a couple of games on

    One particular benefit of the game, other than the initial simplicity and great depth, is the handicapping system, which allows completely satisfactory and highly competitive games between players of disparate skill levels.


    1 November 2011 at 8:37 am

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