In a recent data upgrade - Google added 3D buildings to Tokyo. The Kokugikan is at: 35°41'49.35"N 139°47'36.35"E The roof doesn't slope - but its not bad. Google Earth measures The Sumida River as some 135 metres or 445 feet across near the Kokugikan - quite a distance for the Yobidashi to have practised. Best Wishes - John -- John Tilley