«وَهِيَ الْوُصُولُ إِلَى شَيْخِ أَحَدِ الْمُصَنِّفِينَ مِنْ غَيْرِ طَرِيقِهِ»
“Reaching a compiler's teacher through a route other than his.”
Suppose al-Bukhārī related a report from his teacher Qutaybah. A later hadith scholar obtains the same report through an independent route reaching Qutaybah without passing through al-Bukhārī. This is muwāfaqah at al-Bukhārī's teacher.
Its essential features are the same teacher and an independent alternate route. Differences in the number of links then permit a further comparison of elevation or descent.