&nbsp;This study aims to elucidate the design process of the Hosei University Ichigaya Campus Project by Hiroshi Ohe. Ohe often uses the term &ldquo;Konzai-Heizon,&rdquo; which means interminglement and coexistence, to describe his architectural view. To determine the mechanism of the principle of Konzai-Heizon, we collected and analyzed the drawings of the Hosei University Ichigaya Campus Project, i.e., Ohe's debut works, from the planar form viewpoint.<br>&nbsp;We divided the design period of the Hosei University Ichigaya Campus Project into three phases and analyzed the design process in each period based on collected drawings.<br>&nbsp;In the first phase, the 53-year-old pavilion was built to start the Hosei University Ichigaya Campus Project. In the form of the 53-year-old pavilion and Ohe's discourse at that time, the desire to realize modernism architecture that Ohe embraced for a long time since his college life is expressed. The master plan comprised volumetric groups based on geometric forms with the philosophy of modernism architecture like the 53-year-old pavilion, and there is a consciousness to create the axis using the symmetrical planar form. Moreover, we can find an intention to seek monumentality as a traditional architectural characteristic from the president's office, a symbol of the authority of the university, which is situated on the axis.<br>&nbsp;In the second phase, the 55-year-old pavilion was built. From the form of the 55-year-old pavilion and Ohe's discourse, it can be observed that the philosophy of modernism architecture based on functionalism and rationalism continues from the first phase. Conversely, from Ohe's discourse of the later years, it can be seen that he had a doubt regarding modernism architecture and gradually recognized the necessity of fundamental direction change of the project after overseas travel in 1954. In the master plan of the second phase, the consciousness of the axis symmetry due to the planar form of symmetry is further clarified by the addition of a butterfly form. We demonstrate that the form of the butterfly bears the influence of Kenzo Tange who was one of Ohe's classmates during his college days.<br>&nbsp;In the third phase, the 58-year-old pavilion and the 58-year-old pavilion No. 2 were built. In this phase, the project theme shifted from the realization of modernism architecture through the pursuit of functionality and rationality to the acquisition of &ldquo;monumentality,&rdquo; which is an important characteristic that modernism architecture has lost. Ohe said that what is responsible for the &ldquo;monumentality&rdquo; of the university is the &ldquo;community&rdquo; of people and that the student hall was planned as an expression of the same. It can be noted that the design process was a deconstruction of the axis, as seen in the master plan until the second phase.<br>&nbsp;Based on this analysis, it is clarified that the planar form of the Hosei University Ichigaya Campus Project gradually changed from symmetrical to asymmetrical, and it is concluded that the change of the planar form is considered to the beginning of the Konzai-Heizon principle.