Yoyogi National Gymnasium (国立代々木競技場)

The Yoyogi gymnasiums were built for the 1964 Tokyo Olympics. The brief combined two needs: a large swimming venue and a 20,000-seat multi-purpose hall, first conceived to host judo as well, newly an Olympic sport. A site had to be found first: the American military held most of Tokyo's large plots, and only in October 1961, after about two years of negotiations with the United States, was the choice made for the Washington Heights site, where Yoyogi Park and the NHK now stand among other facilities, and where the Olympic village was also placed.

The Ministry of Education entrusted the design to three people: Kenzō Tange for the overall design, Yoshikatsu Tsuboi for the structure and Uichi Inoue for the building services. In 1962 it asked them for the basic and then the detailed designs. The ground brought a difficulty: heavy groundwater inflow, the cost of dealing with which became a new problem. The tender, held twenty months before the Games among five major contractors, was settled only the next day: Shimizu Corporation would build the first gymnasium and Obayashi Corporation the second.

Work began on 1 February 1963 with eighteen months to finish, and ended on 31 August 1964, thirty-nine days before the Games. In October, swimming and diving were held in the first gymnasium and basketball in the second; in November the complex was also the centre of the Paralympic Games.

Seismic retrofitting ran from January 2018 to September 2019, and operations resumed in November 2019. In 2021 it hosted handball at the Tokyo 2020 Games, then wheelchair rugby and badminton at the Paralympics. On 2 August 2021 the two gymnasiums were designated Important Cultural Property, under two criteria: excellence of design and excellence of technique.

The first gymnasium has a suspended roof: two main masts are joined by two main cables, each 280 m long, from which the whole roof hangs. Each cable gathers many wire ropes; at their ends they plunge into the ground, where huge concrete blocks, the anchor blocks, hold them down with the weight of the soil. Beams are laid across the main cables and covered with steel plates, and the hanging members are pre-formed steel frames.

Seen from above, the plan is two offset semicircles facing each other, and the silhouette is a gentle curve. This tomoe plan gives the circulation a clear layout. The ridge of the roof recalls the main ridge and end ornaments of a Japanese tiled roof, and the outer wall of the stands recalls a lattice.

The second gymnasium has a single mast: a main pipe runs in a spiral from the mast to an anchor block, and trusses hung between this pipe and the columns standing around the circular stands stretch the whole roof. The exterior recalls a seashell or a snail shell; inside, the ceiling is conical. With the movable seats stowed, the arena is circular, 41 m across at its longest.

Both buildings are reinforced concrete with a steel frame in part, under a steel-sheet roof covering. The first has two storeys above ground and two basements, the second one storey above ground and one basement. In the first, the suspension leaves a large interior space whose centre rises.

The site hosts sports competitions and cultural events; the first concert in the first gymnasium dates from 1983. That gymnasium used to be a swimming pool in summer and a public ice rink in winter; a floor is now laid all year round, a use planned from the original brief. The floor of the second gymnasium carries a basketball court. Many works of art made for the 1964 Games are scattered across the grounds.

Free visits are not possible, since preparation work and equipment checks take place even on days without events: a visit is requested by telephone through the site's main switchboard. In the first gymnasium, spectators use the Harajuku entrance, facing north, and the Shibuya entrance, facing south; the first, close to Harajuku station, is most often the main entrance. The entrance to the second gymnasium is about 300 m from the grounds' Harajuku Gate along a paved promenade, opposite the first gymnasium's Shibuya entrance.