Fix Berolina notation + Marseille PGN

[vchess.git] / views / rules / Upsidedown / en.pug

p.boxed
	| Pawns start on the 7th rank. Move a knight to promote them.

h3 Specifications

ul
	li Chessboard: standard.
	li Material: standard.
	li Non-capturing moves: standard.
	li Special moves: no castling (and no en-passant).
	li Captures: standard.
	li End of game: standard.

p.
	...(Almost) Only the initial position changes, but this is a very big change.
	In particular, castling would be rather pointless so it's disabled here.
	En-passant captures are impossible because all pawns already reached 7th rank.

h3 Note on initial position

p.
	Since truly random start can allow un-defendable mate in 3 with a knight,
	the kings touch at least one knight in the initial position.
	This allows to move free out of potential check from the very beginning.

p.
	To illustrate this phenomenon, although it's defendable the standard initial
	position allows the attack as 1.Na6 (threatening Nc5-Nd3#),
	forcing the defense Nf3-Ne5. With a knight next to the king you have more options.

figure.diagram-container
	.diagram
		| fen:R1BQKBNR/PPPPPPP/N7/8/8/8/pppppppp/rnbqkbnr:
	figcaption Standard initial position after 1.Na6

h3 Source

p
	| See for example the 
	a(href="https://www.chessvariants.com/diffsetup.dir/upside.html") Upside down chess
	|  page on chessvariants.com.