Magnetic configurations adopted in the Large Helical Device (LHD (Yamada H et al 2009 Fusion Eng. Des.84 186)) experiment are analyzed from the viewpoint of their toroidal boundary shape using a Fourier mode representation. A minimum number of Fourier modes are identified that are necessary to differentiate three representative configurations of LHD: inward shifted, standard and outward shifted configurations. By adjusting these essential Fourier modes, a new configuration having favourable features of both inward and outward shifted configurations is obtained.