The days when Kyoen Kankan was written correspond to the period when the calligraphic style changed from tensho (seal script) to reisho (clerical script), but very few Kinsekibun (words written on metal or stones) such as stone monuments remained when such change, i.e. reihen (change in calligraphic style), occurred in the Former Han period and therefore reihen was only presumed on the basis of a very small number of penmanship.
居延漢簡の書かれた時代は篆書から隷書へと書体が変化する時期に当たっているが、ちょうどその変化＝隷変のあった前漢代にはほとんど碑などの金石文が残されておらず、ごくわずかな書蹟から推測するだけの状態であった。