Landmark & Tower · Nishi-Shinjuku
Shinjuku Sumitomo Building (Sankaku Hiroba) 新宿住友ビル（三角広場）
The 1974 'Sankaku Building', a 210 m triangular tower with a hollow core, reborn in 2020 with a vast glass-roofed public atrium at its feet, one of the largest covered plazas in Japan.
About
One of the first generation of West Shinjuku skyscrapers, the Shinjuku Sumitomo Building was nicknamed the Sankaku Biru (Triangle Building) for its unmistakable triangular plan and the 50-storey void at its centre, visible to anyone in the upper floors. In 2020, after a major renovation, the plaza around its base was enclosed under a dramatic glass roof to create Sankaku Hiroba, an all-weather atrium of more than 3,000 square metres that hosts markets, concerts, sports viewings and exhibitions, with shops and restaurants around the edges. It sits next to the Tokyo Metropolitan Government Building and the Shinjuku I-Land Tower, so it fits neatly into a walk around the West Shinjuku skyscraper district. Look up from the atrium for the best sense of the tower's sharp triangular corner.
Highlights
- Distinctive triangular 210 m tower from 1974
- Sankaku Hiroba, a giant glass-roofed public atrium added in 2020
- Free events, markets and public viewings in the atrium
- Part of the original West Shinjuku skyscraper cluster
- Direct underground access from Tochomae Station
Tips
- Check the Sankaku Hiroba event calendar; on event days the atrium is busy, on quiet weekdays it is a calm, covered place to rest.
- Walk on to the Tokyo Metropolitan Government Building observatories (free) and the LOVE sculpture at I-Land Tower, both within 5 minutes.
- Use Tochomae Station exit A6 to arrive dry on rainy days.
Open in Google Maps · Info checked 2026-10-09
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- Memorial Museum for Soldiers, Detainees in Siberia, and Postwar RepatriatesMuseum · 80 m away
- Eau de Vie (Hyatt Regency Tokyo)Bars & Nightlife · 100 m away
- Tokyo Metropolitan Government Building ObservatoriesVista & View · 180 m away
- Tokyo Tourist Information Center · Tokyo Metropolitan Government BuildingTourist Info · 190 m away
- LOVE Sculpture (Shinjuku I-Land)Statue & Monument · 240 m away
- Tokyo Night & Light Projection Mapping from Tomin PlazaPhoto Spot · 250 m away
- Shinjuku Central ParkPark · 320 m away
- Kumano Shrine (Shinjuku Juniso)Shrine · 390 m away