Abstract
There have been numerous notation studies devoted to manuscripts with artistic elements so far. On the other hand, notation studies dealing with practical materials, such as information documents, have not witnessed much curiosity and interest. Thus, by extracting kana documents in Kamakura Ibun with special focus on the notation of "とん" we wish to reveal the practical realities of an amanuensis. "ん" in Kamakura Ibun, besides the notation of syllabic nasal/geminate consonants, is also used as a variant character for "モ." The use of "ん" as a variant of "モ" is limited to the character sequence of "とん" and it must be denoted in a joint writing so that "ん" can be interpreted as a variant of "モ." Furthermore, the joint writing sequence of "とん" does not necessarily have to correspond to the meaning of a word or phrase. This is referred to as a "fixed binding." "Fixed binding" occurs in other character sequences besides "とん"; it is regarded as a writing system from the Kamakura period, which is not influenced by the place of residence, gender, or social status of the amanuensis.
