As Kurodo who valeted the Emperor at court, Benkan in charge of administrative jobs at Dajokan and Kebiishi no suke responsible for judiciary/police/civil affairs in Heiankyo (Kyoto) were particularly important official positions with a heavy workload, it was impossible for an official to assume these three positions concurrently unless he had an excellent business ability.
特に宮中において天皇に近侍する蔵人・太政官において行政事務を担当する弁官・平安京の司法・警察・民政の実務を行う検非違使佐は仕事量が多く重要な官職であったこのため、それらの職務を同時にこなすことは実務能力に優れた官僚でなければ不可能だった。