# Is castling possible with a pawn promoted to a rook?

I was thinking about some rules and I came up with a really nice question. Is it possible to castle with a pawn promoted to a rook?

If the rules are followed-neither the king or the new rook has moved and king doesn’t move out of or through check-to me it seems to be a legal move.

If it possbile, how would this castling look like? I suspect that the king would go to e3, and the new rook would go to e2, starting from the below diagram.

``````[FEN "8/4P3/8/8/8/8/8/4K3 w - - 0 1"]

1. e8=R
``````
• The promoted Rook is on the eight rank, the King, not to have moved, must be on the first rank: how would castling be even possible? Commented Jul 19, 2017 at 20:42
• Commented Jul 19, 2017 at 21:12
• Please take a look at the pictire of @RemcoGerlich. It is showing this possition. It even was possible before. But now it is restricted by rules. So my question I actually not so bad. I do not understand why somebody is downwoting it. Commented Jul 20, 2017 at 16:16

No, according to FIDE's Laws of Chess, castling has to be done along the first rank.

§3.8.2:

3.8.2 by ‘castling’. This is a move of the king and either rook of the same colour along the player’s first rank, counting as a single move of the king and executed as follows: the king is transferred from its original square two squares towards the rook on its original square, then that rook is transferred to the square the king has just crossed.

3.8.2.1 The right to castle has been lost:

3.8.2.1.1 if the king has already moved, or

3.8.2.1.2 with a rook that has already moved.

3.8.2.2 Castling is prevented temporarily:

3.8.2.2.1 if the square on which the king stands, or the square which it must cross, or the square which it is to occupy, is attacked by one or more of the opponent's pieces, or

3.8.2.2.2 if there is any piece between the king and the rook with which castling is to be effected.

• The rules have evolved over time to exclude more and more of these obscure possibilities. The loopholes are often pointed out / discovered by problemists who produce impossible looking problems which rely on some strange loophole in the rules. Another clever one is that when you promote a pawn it must be to one of your pieces not your opponent's. Old rules didn't have this restriction until someone produced a mate in 1 problem relying on a pawn promotion which uncovered a check with the promoted piece being an opposition knight taking away a flight square from the king. Commented Jul 19, 2017 at 21:13

This question really needs a diagram with this position:

``````[FEN "8/8/4P3/3p4/2p3p1/1pP1kPPp/1P5P/R3K2R w KQkq - 0 1"]

1. e7 Kd3 2.e8=R gxf3 3.O-O-O#
(1... Kxf3 2.e8=R d4 3.O-O#
(2... Kg2 3. null {O-O-O-O#!}))

``````

White to mate in 3.

Tim Krabbé and Max Pam found the loophole in the rules that you are asking about -- when they composed this problem in 1972, the promoted rook did indeed enable castling, as the rules only talked about a rook that hadn't moved yet! The rule was changed because of this problem.

The solution is beautiful as there are three different castlings involved:

1. 1.e7 Kd3 2.e8=R gxf3 3.0-0-0#.
2. 1.e7 Kxf3 2.e8=R d4 3.0-0#.
3. 1.e7 Kxf3 2.e8=R Kg2 3.0-0-0-0#!.
4. 1.e7 Kd3 2.e8=R Kc2 3.0-0-0-0#!.
• chess.stackexchange.com/questions/31780/… gives the original discoverer of the idea as Conrad Staugaard in 1907. He was a Danish social banker, who also wrote children's stories, and in his memory this joke is termed Staugaard castling in PDB. We are living in the golden age of Staugaard castling, and I hope the usage spreads. Commented Jun 28 at 5:25
• Castling with a promoted rook should be O-O-O-O-O-O Commented Jun 29 at 10:16

It used to be a thing(Krabbe), but FIDE edited its rules to be more specific, so that a king could only castle sideways. So, sadly, it isn't possible nowadays.