In "朝鮮を知る事典"(Encyclopedia to know Korea) published by Heibon-sya, Isshinkai is called 'pro-Japanese order-taker organization' with the mention that they cooperated as spy other than their outer activities.
平凡社の『朝鮮を知る事典』では、一進会を「親日御用団体」と呼び、表立った運動以外にスパイ活動などにも協力したとしている。