# Upper or lower case... who is white?

English Tal
Posers and Puzzles 03 Sep '06 13:28
1. English Tal
Phoneless
03 Sep '06 13:28
rObOkbOr
pppppppp (lower case p's)
OONOOOOO
OOOOOnOO
OOOOOONO
OOnOOOOO
PPPPPPPP (Upper case p's)
ORBKOBOR
2. celticcountry
03 Sep '06 15:04
Nice Puzzle.

Lowercase
3. BigDoggProblem
Just...the Dogg
03 Sep '06 17:494 edits
Originally posted by English Tal
rObOkbOr
pppppppp (lower case p's)
OONOOOOO
OOOOOnOO
OOOOOONO
OOnOOOOO
PPPPPPPP (Upper case p's)
ORBKOBOR
The Uppercase army has a different parity than lowercase army (one has made an even number of moves, and the other an odd number of moves, depending on how the board is rotated). A difference in parity happens only after White has moved. Since a lowercase 'n' is giving check to the enemy K, the lowercase pieces must be White.

Proof Game:
1.Nf3 Nc6 2.Ne5 Nd4 3.Nc6 Nf6 4.Nxd8 Nd5 5.Nc6 Ne3 6.Nc3 Nxd1 7.Nd5
Nc3 8.Na5 Ncb5 9.Nc4 Nf3+ 10.Kd1 Rg8 11.Nf6+

Edit: I knew this looked familiar. R. Smullyan, Chess Mysteries of Sherlock Holmes, p. 87.
4. English Tal
Phoneless
03 Sep '06 19:24
Originally posted by BigDoggProblem
The Uppercase army has a different parity than lowercase army (one has made an even number of moves, and the other an odd number of moves, depending on how the board is rotated). A difference in parity happens only after White has moved. Since a lowercase 'n' is giving check to the enemy K, the lowercase pieces must be White.

Proof Game:
1.Nf3 Nc6 ...[text shortened]... t: I knew this looked familiar. R. Smullyan, Chess Mysteries of Sherlock Holmes, p. 87.
You got me. Touche!