Originally, Oraimono was a collection of model sentences for letter-writing, but later it developed to include social knowledge and common sense, and by the period of the Northern and Southern Courts, "Teikin Orai" was created.
往来物は当初は文書作成のための文例集でしかなかったが、次第にその文面の中に社会常識や知識を盛り込んだものへと変化を遂げていき、南北朝時代(日本)には『庭訓往来』が著された。