I found a cipher that shifts like a chessboard—think you can outmaneuver it?

Here’s the key and the board. The cipher works like a chessboard – each letter corresponds to a square. For the key, use the numerical value of the square’s file (a=1, b=2 … h=8) plus its rank (1‑8). So the shift for a letter is (file + rank) mod 26. For example, a1 gives 1+1=2, so shift by 2, b1 gives 2+1=3, etc. Board (files a‑h, ranks 1‑8): a1 b1 c1 d1 e1 f1 g1 h1 a2 b2 c2 d2 e2 f2 g2 h2 a3 b3 c3 d3 e3 f3 g3 h3 a4 b4 c4 d4 e4 f4 g4 h4 a5 b5 c5 d5 e5 f5 g5 h5 a6 b6 c6 d6 e6 f6 g6 h6 a7 b7 c7 d7 e7 f7 g7 h7 a8 b8 c8 d8 e8 f8 g8 h8 Drop your message through that map, and see if the pattern breaks. Good luck.