Check out Atomic Chess, our featured variant for November, 2024.

Enter Your Reply

The Comment You're Replying To
Alan Baljeu wrote on Fri, May 13, 2005 02:18 AM UTC:
Here's a fair way of shuffling the pieces.  All 960 positions are equally
probable, and no extra equipment is needed.  It works by splitting the
placement into two phases for dark and light squares.

1. Randomly shuffle the 6 pieces not including the Bishops.  Divide these
pieces into two groups of 3 each.
2. Take the first 3 pieces and one bishop.  Shuffle these 4 pieces. 
Place
them on a1, c1, e1, and g1.
3. Take the remaining pieces and 1 bishop, and randomly shuffle them. 
Place these pieces on b1, d1, f1, and h1.
4. Correct the king position by swapping with a rook if needed.

Here's the math: 
The first shuffle yields 6-choose-3 or 6*5*4/3/2/1 ways to divide the
pieces.
The second shuffle yields 4*3*2 permutations of 4 pieces.
The third shuffle yields  4*3*2 permutations of 4 pieces.
Divide by 2 because the knights are the same.  
Divide by 6 because of the king/rook unshuffle.
End result = 5*4*4*4*3 = 960 positions.

To make the shuffle totally fair, label the bottom of your eight pawns
RRRBBNNQ and shuffle them instead of your pieces.

Edit Form

Comment on the page Fischer Random Chess: Manual Procedure for Generating Piece Plac

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.