A novel type of stellarator device, the helical post stellarator (HPS), is introduced. Calculations are given for a particular HPS configuration, the single-helix stellarator (SHS) featuring a single-helix centre post. This configuration is significantly different from all previously known stellarators due to the combination of its unique geometrical characteristics and physical properties. Among these are the facts that the helical magnetic field has only one toroidal period (N = 1), the plasma has an extremely low aspect ratio, , and the variation of the magnetic field, B, along field lines features a helical ripple entirely on the inside of the torus. Among the main advantages of an HPS for the fusion program are an extremely compact, modular, and simple design compatible with significant rotational transform, large plasma volume, and improved particle transport characteristics.