Check out Grant Acedrex, our featured variant for April, 2024.

Enter Your Reply

The Comment You're Replying To
H. G. Muller wrote on Sat, Oct 8, 2016 09:28 AM UTC:
files=10 ranks=10 holdingsType=1 promoZone=1 maxPromote=1 promoChoice=N*D*B*R*L*Q*U royal=9 graphicsDir=/graphics.dir/alfaeriePNG35/ squareSize=35 whitePrefix=w blackPrefix=b graphicsType=png darkShade=#2F2F8F lightShade=#DFDFDF oddShade=#9F2F2F rimColor=#000000 coordColor=#FFFFFF borders=0 firstRank=1 symmetry=mirror pawn::::a3-j3 knight:N::::10 dragon::DDAA::a1,j1 (anglican) bishop:B:BmW:bishop:d1,g1 prince consort::mQK:king:f1 rook::::b1,i1 lion::mQcpQ::b2,i2 unicorn::BNN::c1,h1 royal Queen:Q:nQ:queen:e1

Caïssa Britannia

This very interesting variant contains some rather uncommon pieces, which made it a good candidate for the 'Diagram of the Week'.

Color coding of moves:

  • move or capture (sliding)
  • move or capture (jump)
  • non-capture only
  • capture only
  • moving into or passing through check

Passing through check

The most interesting aspect (and leading motive of the theme) here is of course the use of a powerful slider as royal piece. The brilliant idea of not allowing it to pass through check makes this work. Especially since you can pass through check to capture the opponent's royal. This fits with the interpretation that the Royal Queen can be taken en passant by any other piece, whenever she has made a multi-step move: if you use the multi-step move to capture the opponent's royal then you don't have to fear the e.p. retalliation, as the game is already finished.

This idea posed a challenge to the diagram, however, as originally this was made to display pseudo-legal moves. In this case that would be rather confusing. I could of course have switched it to displaying only fully legal moves, but this can sometimes be very confusing too, if you happen to click on a pinnend piece without realizing it, and only get to see part of the moves, those that stay on the pin ray.

So the solution I finally implemented is to keep showing pseudo-legal moves, except in the case of a royal. Then the diagram first calculates all pseudo-legal moves of the opponent (under the fiction that any target square would be occupied by a piece of us), and mark the thus attacked squares. Any move of our royal that would go to, or pass over such a marked square would then highlighted in gray. (Drag the Royal Queen to b6, and select it,to see what I mean.) Thus it still always shows you how the royal piece could move peudo-legally, but warns you about the passing through / into check. In orthodox Chess such a thing would only happen in the case of castling.


Edit Form

Comment on the page Caïssa Britannia

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.
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.