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[eelik]

Coordinate system, grid and origins in the PCB Editor

Introduction This article originally described version 6.0. The coordinate system and origins haven’t changed as of v9.0. KiCad is a CAD system with 2D data which needs coordinates to mark locations of items. In theory it’s possible to have a CAD system which relies completely on constraints, not coordinates, but KiCad can’t be like that. There must be an internal coordinate system and all explicitly defined locations must fit to that system. The layout editor has a resolution of 1 nanometer; …

A bit outdated but essentially correct; however, it doesn’t answer the question. It’s the Grid origin and as Piotr said, you can set it to 0,0 (for example from Edit → Grid Origin menu) and it disappears.