You'll need to know about:
- A game that has existed for over 1500 years
- A game that doesn't exist
- ♞ → I → II → III → ...
- Answer = Xxxxxxxxx
You'll need to know about:
Okay.... I googled "A game that doesn't exist" and wound up with "Polybius (square)" which also came up in the commentary below. Hadn't heard of that before.
A game that has existed for over 1500 years" presumably refers to Chess. I thought that might be the 'key' for a simple version of the square or an 8x8 square but it didn't work, nor did other keys like "Polybius", so I abandoned this effort for some time.
Coming back to this puzzle, I did some research on Polybius squares and discovered...
There is something called a 'hybrid polybius playfair cipher'. I don't understand it completely but something that caught my eye was that the resulting encoding is a string of numbers of length N where N is approximately twice the length of the plain text.
EDIT: Like I said, I am not very knowledgeable about this cipher stuff. I think the BASIC Polybius cipher ALSO maps to a string of numbers of length N where N is twice the length of the plain text, so that is what I ended up using. I just had to look at the hybrid one before I realized what the basic one was doing.
You see where I am going with this. The answer is Xxxxxxxxx, 9 digits, and there are 18 marked destination squares on the board. So, we need to map each destination square to a number, and then decrypt it using the above algorithm.
An obvious way to map each destination to a number is by mapping the minimum # of hops the knight must travel to reach the square.
I came up with this table:
1 I
3 II
1 III
1 IV
3 V
3 VI
4 VII
4 VIII
1 IX
5 X
4 XI
2 XII
2 XIII
4 XIV
3 XV
3 XVI
2 XVII
2 XVIII
This gives us encrypted text of "13 11 33 44 15 42 24 33 22" which I plugged into a basic Polybius decoder.
Again, using 'CHESS' as the key didn't produce a valid result. But then I tried no key (plain alphabet A-Z without J) and got the result:
CANTERING
Which seems like a suitable answer for a knight's journey! Nice puzzle!