This concrete house in Tokyo was designed by Japanese firm Apollo Architects & Associates for a family that regularly accommodates foreign exchange students (+ slideshow).

As well as two bedrooms and a large family living room for the house's main occupants, Apollo Architects & Associates included a pair of guest bedrooms that open out to a private terrace at the front of the house.

"One of the key design concepts is to respect the privacy of the family and guests to achieve comfortable and relaxing lifestyles," said studio principal Satoshi Kurosaki.

The terrace is invisible to people passing on the street because it is hidden behind stainless steel louvres, which interrupt the raw concrete that otherwise dominates the house's exterior walls.

"The authentic and solid materiality of concrete is contrasted by sharp stainless steel louvres and this facade gives a touch of elegance to the streetscape of the neighbourhood," added Kurosaki.

Named Calm, the three-storey residence is located in Bunkyo, just north of central Tokyo.

Rooms are arranged around a courtyard in the south-east corner of the building. On the ground floor, it sits adjacent to a music room and a traditional Japanese room that can also function as a spare bedroom.

Sliding doors allow all three spaces to open out to one another, as well as to the entrance hall and dining room behind.

"The floor can be used as a large open space welcoming many guests on occasions such as lectures, parties and more," said the architect.

Balconies overlook the courtyard from the first and second floors above, plus a steel staircase connects it with a terrace on the roof of the building.

The living and dining room occupies the majority of the second floor, creating a space big enough to host a large group. A kitchen lined with mosaic tiles runs alongside and is lit from above by a narrow rectangular skylight.

Guests also have access to a separate bathroom, which is located on the ground floor.

Photography is by Masao Nishikawa.

Here's a project description from Apollo Architects:

Calm

This three-story residence is designed to function not only as a house but as a guesthouse that occasionally accommodates foreign guests and exchange students. It is made of concrete using wood formworks composed of 40mm-wide cedar.

The authentic and solid materiality of concrete is contrasted by sharp stainless steel louvres covering the second floor window, and this facade gives a touch of elegance to the streetscape of the neighbourhood. Louvres effectively provide security and privacy at the same time.

On the first floor, a Japanese-style room, which is used as guest room, is located in the back. It is attached to a courtyard enveloped in exposed concrete walls with inscribed horizontal patterns of cedar formworks. By opening the sliding doors, it is seamlessly connected to open space facing the street.

The first floor can be used as a large open space welcoming many guests on occasions such as lectures, parties and more. Toilets and bathrooms for guests are located next to the entrance hall. A soundproof music studio is located at the end of the entrance hall. It is illuminated with soft natural light from the courtyard filtering through the translucent glass facade.

On the second floor, main bedroom and child's room are located adjacent to the courtyard. Each room has a private courtyard and individual or common bathroom attached. One of the key design concepts is to respect privacy of the family and guests to achieve comfortable and relaxing life styles.

Spacious family room with an attached bathroom is provided on the third floor. By fully opening up wide stainless steel windows, the interior space is integrated with the courtyard of exposed concrete. One can access the roof balcony by exterior stairs from the third floor.

Our goal is to create an ultimate space for relaxation, like a hotel lobby or a salon, where one can feel free to enjoy himself/herself and appreciate elegant Joseon Dynasty-style furniture and art works that are placed here and there.

The interior and the exterior merge into each other at intermediate zones, and the host and the guests gather in harmony. This very atmosphere represents the warm welcoming hospitality of the Japanese culture.

Architecture: Satoshi Kurosaki/APOLLO Architects & Associates
Location: Bunkyo ward, Tokyo
Date of Completion: April 2013
Principal Use: Private Housing

Structure: Reinforced Concrete
Site Area: 125.81 sqm
Building Area: 88.05 sqm
Total Floor Area: 225.67 sqm (70.55 sqm/1F, 74.53 sqm/2F, 73.67 sqm/3F, 6.92 sqm/PHF)

Structure Engineers: Masaki Structure (Kenta Masaki)
Facility Engineers: Shimada Architects (Zenei Shimada)
Construction: Maekawa Construction
Exterior Finish: Exposed Concrete
Floor: Ash Black Oil Flooring
Wall: Stucco
Ceiling: Stucco