data structure for representing non square board game

I have trying to design a board game, which is not square. Here we have 2 different types of pieces(attacker & defenders). Both can move to any adjacent free intersection. The attacker player can also jump on defender player if there is empty space in the adjacent intersection in the same line. Considering these cases i can think of storing the board as array. But this is not a right choice, as i need to harcode attackable position from each indexes. need your suggestions for designing this board. The board game