The study aims to reveal Charles-Edouard Jeanneret’s theories of urban morphology in the unpublished manuscript “La construction des villes” through the concept of parti, and to clarify the ideological background of the manuscript. This paper deals with the parti of city blocks.

 In chapter one, the background and structure of “La construction des villes” are briefly reviewed. Emery’s edition of “La construction des villes” consists of the esquisse of 1910, texts of 1910, and résumé of 1915. This study deals with the texts of 1910, which is the main part of the manuscript.

 In chapter two, the meaning of parti is examined. It is known that parti referred to the basic concept or layout of architecture in École des Beaux-Arts in the nineteenth century. However, it is not clear what parti means in urban design. In “La construction des villes, ” there are eighteen instances of the word parti, and the word often refers to the elements consisting of a city, such as city blocks, streets, and plazas. Jeanneret applied parti, which had been used in architecture, to urban design to mean the types of elements of the city, and discussed parti as a theme of the manuscript mainly regarding city blocks, streets, and plazas.

 In chapter three, the manuscript is examined carefully. This study deals with the elements of a city: namely city blocks, streets, and plazas, in that order. First among the subjects of this paper is the city block.

 In chapter four, descriptions of the parti of city blocks, including sentences without the word parti, are extracted. These partis are then classified into three patterns: type of courtyard, grouping, and isolation. To evaluate them, Jeanneret used the following criteria: hygiene, the number of houses per city blocks, the economy of façades, the beauty of residential yard perspectives, the diversity of street perspectives, street-facing façades, and the use of the right angle. These criteria are classified as practical or aesthetic. The former is based on principles of hygiene and of economy and consists of hygiene, the economy of façades, and the number of houses per city block. The latter comprises the beauty of residential yard perspectives, the diversity of street perspectives, street-facing façades, and the use of the right angle. It is founded on principles of the use of the right angle, diversity of perspectives, and visual closure. Furthermore, it is noteworthy that Jeanneret praised visual closure and criticized open space by using the word “vide.” On the one hand, the principles of visual closure and diversity of perspectives have a picturesque caractère, while on the other hand the use of right angle has a monumental caractère. Jeanneret evaluated positively both monumental right angles and picturesque curves, and signs of Le Corbusier’s preference for right angles seem already apparent.

 In the concluding chapter, analogies between famous housing plans and Jeanneret’s diagrams are pointed out. The row house diagram criticized by Jeanneret for its monotony resembles an industrial village in nineteenth-century England, for example, and the hexagonal diagram by Jeanneret is similar to the hexagonal alternative to rectangular plans in early nineteenth- and twentieth-century America. Therefore, it is suggested that Jeanneret’s thoughts on housing development did not stray from the norms at that time.