the building is composed of 13 independent steel-ribbed shafts (tubular columns: mainly steel-tube truss construction) and 7 steel-ribbed slabs ("honeycomb"slabs: sandwiched steel-plate construction), giving each floor a different floorplan. basement (b1) structures feature seismic energy-absorbing mechanisms.
upper vents on double glass ("double skin") south facade reduce air-conditioning costs. opening the vents in summer creates a cooling updraft; closing the vents in winter creates an insulating layer of air to seal in heat.
tubes for light wells, ducts, vertical mobility
the tubular column structures serve as light wells, with rooftop devices to reflect sunlight down the tubes into the building. and also as vertical connector "pipelines"for network cables, wiring, elevators and stairways.
site area: 3,948.72m
building area: 2,933.12m
total floor area: 21,682.15m
max height: 36.49m
size: 2 floors below ground + 7 floors above ground + rooftop
structure: steel-ribbed with partial reinforced concrete (rc) construction
construction: 17 dec 1997-10 aug 2000
construction cost: approx 13 billion yen
opening: 26 jan 2001