This study will evaluate the antiviral efficacy of sofosbuvir (SOF)/ledipasvir (LDV) fixed-dose combination (FDC) tablet with or without ribavirin (RBV) in treatment-naive or treatment-experienced Japanese participants with chronic genotype 1 HCV infection. Participants receive 12 weeks of treatment and continue assessments during a 24-week posttreatment follow-up period.