However, there is another theory which claims that Seiwa-Genji, which was traditionally believed to be the line of Imperial Prince Sadazumi, was the blood line of Emperor Yozei (Imperial Prince Sadazumi's older brother).
ただし、これについては異説があり、従来の貞純親王流とされる清和源氏は陽成天皇（親王の兄）からつながる血筋だとする説もある。