Another superb café. Locations all over Japan. These cafés are famous for their giant matcha sundaes. http://www.nanasgreentea.com/en/
Marunouchi Café @ The Marunouchi Hotel
A bit upscale – and afternoons only, but worth a stop if you’re in the area.
History of Ekiben Lunch Boxes – An Invaluable Part to Any Shinkansen Ride in Japan | tsunagu Japan
https://www.tsunagujapan.com/japan-ekiben/