Akasaka 1-Chome District

The Akasaka 1-Chome redevelopment combines offices, residences, retail and greenery in a major expression of the urban-garden concept in central Tokyo. Its principal building, Akasaka Intercity Air, has 38 above-ground floors and stands approximately 205 meters tall. Extensive public planting and paths surround the tower and occupy podium roofs, while sky gardens on upper levels provide outdoor retreats in the busy city. A contemporary glass curtain wall is punctuated by setback terraces with extensive planting, creating a layered vertical-garden effect that enriches the skyline and moderates the microclimate. Underground connections link nearby stations, while plazas, public art and continuous walking routes improve the ground-level environment. The project has become a new Akasaka landmark and a destination for relaxation.

Design Concept and Features

Bringing Nature into the City: The name Air expresses the introduction of fresh natural elements into a dense urban setting. The Urban Retreat concept creates a large, publicly accessible corner plaza planted with mature trees and flowers. Terraces and double-height planted spaces occur at intervals up the tower, incorporating water, stone and seasonal planting. Located beside office exchange lounges, these sky gardens encourage staff to take breaks and meet outdoors. Serviced apartments on lower levels have dedicated terrace gardens. Together, these spaces create a vertical green community in which architecture and nature coexist.

Comfort and Sustainability: Air circulation through the atrium and core works with terrace planting to reduce heat-island effects. Automatic blinds within the double-skin glass facade limit heat gain and glare while maintaining bright offices. Natural stone and timber in lobbies and outdoor areas provide warmth and connect the building with its landscape. Geothermal energy and greywater recycling contribute to LEED Gold or higher performance. Form, space and building systems together offer a healthier, more nature-connected approach to high-rise development.

Leadfu's One-Stop Integrated Services

We integrated the sky-garden structures and curtain wall. Because projecting planted terraces carry substantial loads, we coordinated embedded steel reinforcement in concrete slabs to support large planters and soil, with appropriate waterproofing and drainage. We also coordinated installation of the ventilated double-skin curtain wall. Precise control of cavity widths and vent positions was essential. Large units incorporating inner glazing, ventilation-louver frames and outer glazing were preassembled in the factory to reduce work at height. Factory commissioning of sensor-controlled blinds and operable panels improved accuracy and allowed rapid installation and operation. At underground passage connections, we provided waterproof enclosure solutions using specialized steel plates and insulating-glass walls to balance earth-pressure resistance with daylight. Our coordinated service aligned architectural, structural, building-services and landscape interfaces throughout this complex project.

Spatial Planning and Facade Design

• Integrated Functions:Akasaka Intercity Air contains premium offices, serviced apartments, retail, restaurants and meeting facilities. The tall, bright office lobby connects directly to a planted second-floor terrace. Serviced apartments have separate entrances and elevators, while shared facilities include a gym and conference center. Basement level one contains dining and underground connections to Tameike-sanno and Akasaka-mitsuke stations, supporting commuting and public access.
• Energy-Efficient Facade:Open louvers on the lower podium allow natural ventilation between plazas and retail areas. The tower uses a high-performance double-skin Low-E glass system with sensor-controlled blinds responding to sunlight to reduce cooling demand. Movable screens and glass enclosures around terraces adjust the outdoor microclimate, providing shelter during strong wind, rain or snow and opening for ventilation in good weather.
• Sustainability and Innovation:The project combines environmental certifications with integrated technology. A smart building-management system coordinates air conditioning, lighting and irrigation for precise energy and landscape management. Large basement tanks collect rainwater and air-conditioning condensate for irrigation and toilet flushing, reducing potable-water demand. Structural dampers improve seismic performance and protect elevated planting. Approximately 3,000 square meters of ground-level greenery and multiple sky gardens provide unusual public landscape benefits in central Tokyo, reflecting environmental and social commitments.

The Akasaka 1-Chome redevelopment has earned recognition for its extensive urban greenery and high-quality spaces. Akasaka Intercity Air brings nature into a skyscraper and offers moments of shade and quiet in the city center. It enriches Tokyo's skyline while demonstrating an approach to urban development that integrates nature and improves everyday life.