Re: Proposal to add standardized variation sequences for chess notation

From: Michael Everson <>
Date: Sun, 2 Apr 2017 08:19:00 +0200

> On 1 Apr 2017, at 23:49, Philippe Verdy <> wrote:
> I think it's all about sizing so that white or black cells will align, independantly of the piece that may be within it.

A white knight may stand alone in text, in which case no variation exists for display beyond the base glyph in the font.

A white knight may need to be represented with specific em-square-related metrics within the font, in two variations, one with no fill on the background of the em-square indicating the piece on a white square, and one with a (typically ///-shaped) fill indicating the piece on a black square.

> However if FE00 and FE01 give the background color distinction, why is the base different (25A1 vis. 25A8) for the empty cell, when it is no different for the same piece (in the same white or black color) ?

In the second row in Figure 3, a chessboard is given without any variation selectors at all. This is not beautiful presentation but it is nevertheless legible in plain text. This is more advantageous to the user than having e.g. WHITE SQUARE display both as white with em-square square metrics and as hatched with em-square metrics.

> I see the separation of the base only for the borders (touching outside the checkers board),

The characters used for the horizontal and vertical borders and corners are optional and do not require variation selectors. In a chess font they only require to be drawn with the appropriate metrics to match up with the board squares.

> which may also be reduced to a minimal thin edge over a small margin... or nothing at all (completely transparent) if the font already includes a thin contrasting cell on the squares (e.g. grey ridges with 3D effects). The outer backdound on which these borders are drawn may also be already contrasting with another color (yellow, green, blue), and checkers may also use other pairs of contrasting colors (e.g. beige/ivery vs. brown):

Those proposal is about black and white glyphs for ordinary printing of plain text with appropriate font glyphs in the conventional way of displaying chessboard data. In lead type, a white knight in a white square was a separate character from a white knight on a black square. This proposal uses variation selectors to select such glyphs, preserving character identity of chess pieces as already encoded. The alternative would be to encode *WHITE CHEESE KNIGHT ON BLACK SQUARE which when mooted in the past was rejected.

> The FE00 and FE01 select an Emoji style


> with more freedom in shapes and colors for the piece and more precise and coherent sizes but a required square cell. Their absence just means an isolated piece outside the checker board and without required backgrounds or without monospaced margins, suitable for inclusion in text.

The proposal does no more nor less than it says it does. It has been carefully thought out and tested in font implementation, typeset as you see in the proposal in a program which respects the OpenType features.

Michael Everson
Received on Sun Apr 02 2017 - 01:19:38 CDT

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