Check out Janggi (Korean Chess), our featured variant for December, 2024.

Enter Your Reply

The Comment You're Replying To
H. G. Muller wrote on Thu, Mar 7, 2013 09:31 PM UTC:
To make absolutely sure I have a good calibration of the Pawn-odds score, which is the yard stick I measure all piece-value differences against, I did a 2N vs R+P match. (I had never done that before with the mating-potential-aware Pair-o-Max.) This ended in favor of the Knights with 64% score, which is an advantage of 0.93 times the Pawn-odds score (which is ~15%). The difference R-N has been implicitly measured in 2 steps, the N+N+P vs R4+R4 difference and the R4+P vs R difference. I quoted 20cP and 0cP for these earlier, but I should really have said these were 0.2 and 0 times Pawn-odds. From the latter it follows R4 = N + 0.6, and R = R4 + 1, so that R = N + 1.6. While now we have 2N = R + 1.93.

Some algebra then shows 2N = N + 1.6 + 1.93, or N = 3.53 times Pawn odds. With the Kaufman value N = 325 cP, this gives

Pawn odds = 92 cP (= 15% score advantage)

This agrees excellently with the conclusions drawn from 2W vs N, but are a bit more reliable. R = N + 1.6 = 3.52 + 1.6 = 5.12 x Pawn odds, or 472 cP. That is 28 cP below the classical value, but it is for a Rook trapped behind Pawns. Recalibrated, R4 becomes R - 92cP = 380 cP.

The measurements of R2, R3 and R4 have become a bit ambiguous, as these pieces should also suffer from the quarter-Pawn penalty behind Pawns. But in some of the starting positions they were combined with Pawn odds, and although they never started on the open file caused by the Pawn removal, one of them was nevertheless very close to it. So in those cases one of the two Rn might have suffered appreciably less penalty.

So I really should redo these measurements under better controlled conditions. I am a bit dissatisfied with how long they take, though. I am currently playing 40 moves/min games. Perhaps I should switch to 40 moves/10 sec games. I am not sure that Fairy-Max is strong enough to deliver sufficient game quality at those speeds, though. Perhaps I should make its search a bit less minimalstic, using real move sorting, so that it can use killer heuristic and all these other nice techniques to reduce branching factor...

Edit Form

Comment on the page Buypoint Chess

Conduct Guidelines
This is a Chess variants website, not a general forum.
Please limit your comments to Chess variants or the operation of this site.
Keep this website a safe space for Chess variant hobbyists of all stripes.
Because we want people to feel comfortable here no matter what their political or religious beliefs might be, we ask you to avoid discussing politics, religion, or other controversial subjects here. No matter how passionately you feel about any of these subjects, just take it someplace else.
Avoid Inflammatory Comments
If you are feeling anger, keep it to yourself until you calm down. Avoid insulting, blaming, or attacking someone you are angry with. Focus criticisms on ideas rather than people, and understand that criticisms of your ideas are not personal attacks and do not justify an inflammatory response.
Quick Markdown Guide

By default, new comments may be entered as Markdown, simple markup syntax designed to be readable and not look like markup. Comments stored as Markdown will be converted to HTML by Parsedown before displaying them. This follows the Github Flavored Markdown Spec with support for Markdown Extra. For a good overview of Markdown in general, check out the Markdown Guide. Here is a quick comparison of some commonly used Markdown with the rendered result:

Top level header: <H1>

Block quote

Second paragraph in block quote

First Paragraph of response. Italics, bold, and bold italics.

Second Paragraph after blank line. Here is some HTML code mixed in with the Markdown, and here is the same <U>HTML code</U> enclosed by backticks.

Secondary Header: <H2>

  • Unordered list item
  • Second unordered list item
  • New unordered list
    • Nested list item

Third Level header <H3>

  1. An ordered list item.
  2. A second ordered list item with the same number.
  3. A third ordered list item.
Here is some preformatted text.
  This line begins with some indentation.
    This begins with even more indentation.
And this line has no indentation.

Alt text for a graphic image

A definition list
A list of terms, each with one or more definitions following it.
An HTML construct using the tags <DL>, <DT> and <DD>.
A term
Its definition after a colon.
A second definition.
A third definition.
Another term following a blank line
The definition of that term.