(!castleInCheck && this.isAttacked([x, i], oppCol, "castling")) ||
(this.board[x][i] != V.EMPTY &&
// NOTE: next check is enough, because of chessboard constraints
(!castleInCheck && this.isAttacked([x, i], oppCol, "castling")) ||
(this.board[x][i] != V.EMPTY &&
// NOTE: next check is enough, because of chessboard constraints