Ohnishi, Y. Funakoshi, Y. Koiso, H. Morita, A. Oide, K. Sugimoto, H. JACoW Geneva, Switzerland 978-3-95450-187-8 10.18429/JACoW-eeFACT2016-TUT3BH2 English 143-146 TUT3BH2 ion sextupole emittance optics coupling Contribution to a conference proceedings 2017 2017-07 https://doi.org/10.18429/JACoW-eeFACT2016-TUT3BH2 http://jacow.org/eefact2016/papers/tut3bh2.pdf The SuperKEKB collider has finally come to the first commissioning, Phase 1 without the final focus system and before Belle II detector roll-in. In order to accomplish a extremely high luminosity of 8x10³⁵ cm⁻²s⁻¹, the nano-beam scheme is adopted. Since the vertical emittance is one of keys in this scheme, optics corrections for low emittance tuning are applied. The non-interleaved sextupole scheme is utilized in the arc section. Skew quadrupole-like corrector is equipped for each sextupole. These skew quadrupole-like correctors can correct both X-Y coupling and physical vertical dispersions which induce the vertical emittance. Beta function and physical horizontal dispersion are corrected by fudge factors of quadrupoles and/or horizontal orbit bumps at the sextupoles. Overall optics performance as well as the strategy of low emittance tuning is also presented.