Operation of ILC250 at the Z-pole

ILC (International Linear Collider) is under consideration as the next global project of particle physics. Its Technical Design Report, published in 2013, describes the accelerator for the center-of-mass energies above 200GeV. The operation of ILC at lower center-of-mass energies has not been studies intensively. This report discusses the operation of the ILC at a center-of-mass 91.2GeV and presents a possible parameter set.