Although the systems of the large mercantile families were kept secret, a written manual was sometimes prepared for the guidance of future generations. Such was the case of the Nakai Family which had prepared in about 1828 a manual listing 47 books together with a description of the items to be entered in each. However, no author attempted to formulate a basic theory of accounts and no text book was written. Therefore, as Arthur Woolf states,4 no uniform accounting system existed in Japan. Nevertheless, there were several basic similarities or common characteristics in the isolated systems which were developed independently, probably because of the fact that in order to maintain the effectiveness of a system it must constantly be compatible with the common environment in which it operates.