Ryuichi Ashizawa Architects attach an egg-shaped tomb to a family home in Sakai

Japan-based Ryuichi Ashizawa Architects explored the relationship between architecture and urban loss with their Minami Hanada Tomb – an egg-shaped raised mound attached to a residential project in Japanese port city of Sakai. Celebrating death as a manifestation of life, the project dwells on the ancient Japanese cultural tradition of erecting megalithic Mozu mausoleums – a series of raised burial sites for the imperial classes of Osaka’s Sakai prefecture. While the current design addresses life with spaces centred around activities of the living, it’s the topic of death which often remains unresolved. Interrogating the norms of spatialising loss, Ryuichi Ashizawa Architects (RAA) aimed to normalise building for the afterlife and building for life within the same premises. However, due to the legal prohibitions surrounding zoning laws, residential cemeteries are greatly unwarranted; resulting in the studio’s tomb concept being purely metaphorical. As such, with this unconventional housing brief for a family of three, the architects set out to explore the symbiotic relationship between spaces of living and dead spaces as symbolised by the tomb.

The plan of Minami Hanada Tomb has been orchestrated to clearly demarcate the daily living spaces from the areas with no particular function. The main house accommodating the daily activity spaces is located on the southern half of the site. Constructed using an interior wooden frame with exterior walls in baked cedar, the residence is well integrated with the old houses in the Sakai neighbourhood. This double-skinned structure creates an inner and outer layer; the space in between behaving as a buffer corridor between the ground floor and the rim. With glass walls bounding the rim of the corridor and a traditional earthen flooring, the buffer space fosters a gentle relationship with the outside by allowing easy accessibility to the street.

A galvanised steel gable roof tops the main house with two layers below it - the ground floor houses the kitchen and living room, and the top floor has two bedrooms. The use of diaphanous shoji screens separate or join the rooms on the ground floor as and when desired by the residents. The roof is made to slightly overhang such that the space in between the inside and outside of the second floor forms a loggia decked with wooden flooring. Responding to the residents’ request to create “a library like space where local children and nearby residents could stop,” the architects built bookshelves in the spaces between the inner structural walls facing outwards.

The northern half of the expanse locates the egg-shaped intermediary space comprising of two small domes - the bathroom and the laundry room. Inside the 6.5 meter-high curving tomb, a central oculus allows the gentle filtering of light, creating an intimate space designed for contemplation and inward reflection.

When devising a structural strategy for the building, the Ryuichi Ashizawa Architects concluded that the entire building would be supported by a soft curved egg like “shell” that covered the large hollow space of their symbolic tomb. However, what proved to be most cumbersome was how a strong spherical shell could be constructed naturally with straight and flat wooden members. After a number of futile attempts, the team at Ryuichi Ashizawa Architects devised a bow-shaped framework, which incorporated two pieces of short cut wood together while shifting the cutline and fastening plywood boards for the infills. These were then arranged radially according to the plan and soil was used to further define the curvature of the shell.

The hard shell tomb on the northern end has been designed to behave like a "paperweight", stabilising the entire house, while the rooms on the south side are made up of the earthquake proof wall, integrated with the bookshelf. Positioned on the southern end, the living space has been made using a relatively simple construction technique - wooden beams and posts connected at regular intervals in a chevron with round steel creating a light, structural framework.

During summer the vents in the north dome can be adjusted to allow cool air to passively ventilate the adjoining living spaces, and in the winter months when cool air is less desirable, these fixtures can be closed. The earthen floors of the main house and soil covering of the ‘empty room’ thermally insulate the spaces by storing heat, which is dissipated back into the space during the colder seasons. The retractable celling and shoji sliding doors have been carefully assimilated to permit the creation of an indoor environment unaffected by externalities on closure, while allowing residents to simultaneously monitor their own lighting conditions.