Many methods have been developed to distinguish earthquake foreshock. In this study, we used the rhythm of nine multiplied days in different years to distinguish foreshocks. In this method, we look for earthquakes that conform to the rhythm of nine multiplied days in different years in regions where a small earthquake or earthquake swarm occurred. If one day among the nine in different years occurred close to the day the small earthquake or earthquake swarm occurred, we consider that this small earthquake or earthquake swarm may have been a foreshock. Two examples were identified:the small earthquake before the Yushu M_S7.1 earthquake in 2010 and the small earthquake swarm before the Wenchuan M_S8.0 earthquake in 2008, both of which could possibly have been foreshocks.