Building Shapes on Mita Campus

2021/11/30

Image: Mita Campus North Building

Mita Campus has many buildings, including the Enzetsukan (Public Speaking Hall) completed in 1875, and their shapes vary. In recent years, many skyscrapers have appeared in the surrounding area, but there are no particularly tall buildings on campus, with the tallest being the South Building at 48.3m. This is influenced by morphological restrictions imposed by a certain law. This is what is commonly known as "sunlight shadow regulations."

Sunlight shadow regulations were introduced in the 1976 amendment of the Building Standards Act because the construction of mid-to-high-rise apartments in the 1970s led to sunlight issues becoming apparent and an increase in lawsuits. In Tokyo, it was enacted in July 1987 as the "Tokyo Metropolitan Ordinance on Height Restrictions for Mid-to-High-Rise Buildings Based on Sunlight Shadows," and Mita Campus, including the Chutobu Junior High School and the Girls' High School, is significantly affected by it.

A characteristic of this ordinance is that if an existing building casts a shadow that does not comply with the ordinance, it is not considered an "illegal building" but is instead termed "existing non-conforming," meaning it does not have to be demolished immediately. However, it is not treated the same as a compliant building and faces significant restrictions when constructing new buildings or additions on the site.

The sunlight conditions become even stricter than usual regulations; for example, the exterior walls of new buildings must be at least 4m away from the property line, and the floor area ratio is reduced to two-thirds. However, the factor that most affects building morphology is the inability to cast new shadows on areas already subject to non-conforming shadows. Restrictions are imposed that make it difficult to build not only above non-conforming buildings but also around them. Generally, schools have many long buildings running east-west located toward the north side of the site. In such cases, shadows exceeding regulations tend to fall mainly on the north side; Mita Campus is no exception, casting non-conforming shadows on the adjacent land to the north.

The North Building, which houses the Faculty Club and the North Building Hall at the northernmost part of the campus, clearly illustrates these building morphology restrictions. The roof of this building slopes significantly toward the north, reducing the shadow cast on the adjacent land to the north.

Additionally, to avoid increasing the non-conforming shadows cast toward the Italian Embassy, the exterior walls of the second and third floors on the west side are slanted toward the north. The North Building's shape, which at first glance seems to be a design choice, actually stems from morphological restrictions due to sunlight shadow regulations. When you visit the Faculty Club, I would be pleased if you could look at the North Building from this perspective and think, "So the shape of this wall and roof is due to the influence of regulations."

While these sunlight shadow regulations make it difficult to build high-rise buildings on Mita Campus, whether skyscrapers are suitable for educational settings is a topic that may invite much debate. Personally, I feel that the current height might actually be just right.

(Yu Yanome, Administrative Director of the Senior High School)