On July 11, both the JMA and JTWC upgraded a tropical disturbance to a tropical depression which was near Minamitorishima. On July 12, both the JMA and JTWC upgraded the system to a tropical storm and named it Ma-on. Early on July 13, the JMA upgraded Ma-on to a severe tropical storm. Late on July 13, both the JMA and the JTWC upgraded Ma-on to a typhoon. After absorbing Tokage, Ma-on reached its peak strength on July 16. The PAGASA named it Ineng on July 17.