Chess960 castling question

All Things Chess
1

The rules to Chess960 (“Fischer random”) can be found here, near the end under Guidelines II.

The initial setup of pieces on the players’ back ranks is determined by computer, or randomly in some other way:

  • Each player’s pawns start on the player’s 2nd rank, as usual.
  • Each player’s pieces start on the player’s 1st rank.
  • The players have mirror-image positions, e.g. if there is a white bishop at g1, then there is a black bishop at g8.
  • The player’s two bishops start on squares of opposite colors.
  • Each player’s king starts on a square somewhere between the two rooks.

Castling is executed as follows:

  • The queenside rook is the one that starts on the file closest to the a-file.
  • The kingside rook is the one that starts on the file closest to the h-file.
  • Queenside castling is executed by moving the king to c1 (c8) and the queenside rook to d1 (d8), regardless of where these pieces started.
  • Kingside castling is executed by moving the king to g1 (g8) and the kingside rook to f1 (f8), regardless of where these pieces started.

Of course, the usual castling rules also apply:

  • Neither the king nor the rook can have moved previously.
  • The king may not castle out of check, through check, or into check.
  • All squares (if any) between the king’s starting and ending squares must be vacant (or occupied only by the rook).
  • All squares (if any) between the rook’s starting and ending squares must be vacant (or occupied only by the king).

Note that some castling maneuvers involve the king only, or the rook only. Kg1 castles with kingside rook Re1 by moving just Re1-f1. Or, Ke1 castles with kingside rook Rf1 by moving just Kg1.

Also note that some castling maneuvers involve switching the squares the two pieces are on. Kf1 castles with kingside Rg1 by moving Kf1-g1 and Rg1-f1. This particular castling maneuver may even be executed on move 1!

Question:

  • If the king starts at g1 and the kingside rook at f1, is the player regarded as having already castled (on move 0?), and is thus prohibited from castling again later?
  • OR, may the player castle by moving neither piece, and just stating that he is castling?
  • OR, may the player later castle queenside?

Bill Smythe

2

Note that in your rules above the King starts between the two Rooks, therefore the hypothetical is impossible.

Alex Relyea

3

Oops, you’re right. :blush:

Bill Smythe

4

But if the king starts on g1 and the queen-side rook starts on f1 (king-side rook on h1) then queen-side castling is done with the king moving four squares to c1 and the rook two squares to d1 (or, the f1 rook is moved and then king-side castling is done by hopping the h1 rook over the king to f1).

5

OK, but that part is relatively obvious – even to me, unlike the original question. :neutral_face:

Bill Smythe