['ischemic stroke', 'transient ischemic attack']
['rivaroxaban', 'warfarin']

        Inclusion Criteria: All of below

          -  Acute ischemic stroke or TIA presumed to be cardioembolic origin (within 5 days from
             stroke onset) with mild severity: infarct size on DWI less than 1/3 of MCA territory,
             1/2 of ACA territory, 1/2 of PCA territory, and 1/2 of one cerebellar hemisphere

          -  Atrial fibrillation including paroxysmal atrial fibrillation: atrial fibrillation must
             be documented by ECG evidence (e.g., 12-lead ECG, rhythm strip, Holter, pacemaker
             interrogation) within 30 days before randomization. This could be obtained from a
             notation in the subject's record (e.g., medical chart, hospital discharge summary).

          -  Age ≥19 years

          -  Informed consent

        Exclusion Criteria: Any of below

          -  Chronic renal failure (GFR less than 30ml/min) or severe hepatic impairment

          -  Significant hemorrhagic transformation (parenchymal hematoma type I or II by the ECASS
             definition)

          -  Stroke mechanism of presumed small vessel occlusion: single small subcortical infarct
             in the perforating artery territory

          -  Large hemispheric or cerebellar infarction; larger than 1/3 of MCA territory, 1/2 of
             ACA territory, 1/2 of PCA territory, and 1/2 of one cerebellar hemisphere

          -  Mechanical valve requiring warfarin therapy

          -  Active internal bleeding

          -  Prior history of symptomatic intracranial bleeding

             : patients with asymptomatic bleedings or microbleedings on MRI are eligible for
             inclusion

          -  Major surgery or major trauma within 30 days that might be associated with increased
             bleeding risk

          -  Clinically significant gastrointestinal bleeding within 6 months

          -  Intravenous tissue plasminogen activator use or mechanical embolectomy within 48 hours
             plus 'significant hemorrhagic transformation as described above (exclusion criteria
             2)' or 'large hemispheric infarction or cerebellar infarction as described above
             (exclusion criteria 4)'

             : patients achieving successful reperfusion without hemorrhage nor large infarction
             are eligible for enrollment

          -  Severe anemia: hemoglobin <10 g/dL

          -  Bleeding diathesis; thrombocytopenia (<90,000/µL, prolonged PT (INR>1.7)

          -  Sustained uncontrolled hypertension: SBP >180 mmHg or DBP >100 mmHg

          -  Severe devastating illness, such terminal cancer, hepatic failure; therefore, the
             participants have a life expectancy less than 6 months.

          -  Planned invasive procedure with potential for uncontrolled bleeding, including major
             surgery
      