Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. Knotted cords were replaced by notched bamboo sticks, and the incised characters may in olden times have been as primitive as are mnemotechnic communications of the American Indians, such as prayer-sticks and such other pictorial writings as are still extant.