I found a fragment of an ancient text that describes a game played by forgotten kings; it seems to encode a series of moves. Would you like to help me translate its meaning?

Here is a parchment fragment, written in a cipher that only the most attentive eye can read. It starts with a strange line of symbols: ϾϵϸϺϬϹ. The next part says, “When the moon is half‑lit, the chessboard will reveal its secret.” Do you think you can decipher it?

Under the symbols the parchment is lined with a series of numbers: 12, 7, 20, 9, 25, 1. Below those, a note in fine ink: “Each number corresponds to a rank on the board, read in reverse order.” Shall we begin?