# Why not a 10x10?

Transcript:

Colors:
White - W
Red - R
Yellow - Y
Blue - B
Green - G
Purple - P
Brown - Q

YGRPWYQG
YQRBPPRQ
QRPWBWPP
RWWWBWRW
RYQYBPPY
GGRQWBWP
WWWWWWBW
WWWWWWBQ

Letters:

YOUR.CHA
LLENGE.I
S.TO.FIG
URE.OUT.
WHY.THIS
.GRID.IS
.EIGHT.B
Y.EIGHT.


Hint:

I omitted a tag to make this non-trivial.

Partial solutions and ideas are welcome in either the comment section or the answer section.

This is a really interesting puzzle and the first observation is that the message that can be seen is "your challenge is to figure out why this grid is eight by eight"

Now we consider only the different colours which are available - "yellow, green, blue, red, brown, white, purple" i.e., 7. Note if we don't consider white we have 6 colours.

Incidentally,

6 is the number of different types of pieces that a chess game has "King, Queen, Rook, Knight, Bishop and Pawn".

This gives us the possibility that each colour represents a difference chess piece.

Clearly knowing the movement of knight -- purple is knight [moves such as R--E, H--I, etc are all knight moves]

Similarly, brown is bishop h1, b7, a6, c4, d3, a7, b8 [standard chess coordinate lingo]

Green is a rook [a3 b3 b8 h8] all horizontal and vertical movements

Yellow has to be queen

This leaves us with pawn and king. Since, king moves only one square at a time we can quickly figure out blue is king (it began with castling!!!) and red is pawn (a4, a5, axb6, bxc7, c8=q promotion qc3, qg7, qg5)

So, we have found that each colour represents the movement of a chess piece due to which this is a chessboard in actuality.

Also, a chessboard is 8x8 which is why this board has to be an 8x8

The tag left out was probably

• I've taken the liberty of placing your answer in spoiler blocks, for the benefit of future solvers. If you'd like to see how that's done, simply start another edit and take a look. Commented Jan 19 at 13:35
• The reasoning behind the explanation was hard for me to understand until I understood that each color represents rot13(n frdhrapr bs inyvq pbafrphgvir zbirf, naq n zbir qbrf abg vaibyir vagrezrqvngr fdhnerf).
– Neo
Commented Jan 19 at 18:37
• Thanks so much @AxiomaticSystem, made the answer much better!! Commented Jan 20 at 3:12
• @Neo I think your observation is the key that is missing from the current answer. Commented Jan 30 at 14:31
• I understand the answer, but I don't see why it cannot be on a 10x10? Just a bit non-standard. Commented Jan 30 at 14:33