Behind the background of the tale of Tesso was intense power struggle in the Buddhist region at the end of the Heian period and also it is a historical material to pass on to today the picture of the sogai (rat damage) at that time.
鉄鼠の物語は平安末期における仏教界の激しい勢力争いを背景としたものであり、また、当時の鼠害（そがい）の様子を今に伝える史料でもある。