{Japanese Text Layout---Basic Issues} {YABE Masafumi} {This part of tutorial presents basic issues concerning page formats and typesetting methods applied to the main text of a Japanese book with reference to the typographic characteristics of Japanese writing system. The issues to be discussed are threefold. The first section focuses on the text direction, vertical or horizontal writing mode, which depends on an editorial decision and commands in many ways the page layout as well as the printed forms of a Japanese text. The second section concerns the typesetting methods applied to the basic Japanese text as a sequence of characters without spaces between words, and illustrates relevant typographic building blocks in line composition rules with emphasis on the functional importance of punctuation marks and their surrounding spaces for line and paragraph adjustments. The last section addresses several issues about the methods of mixed composition of Japanese and Western texts, presenting major technical problems relating to differentiation and harmonization of typographically heterogeneous elements in sequential texts: Western text in the context of main horizontal or vertical Japanese text as well as Japanese text in the context of main Western text.}