Tokyo's underground consists of miles of pedestrian walkways, extensive shopping arcades and a subway network. It stretches for hundreds of kilometers between more than 200 subway stations. Even with a map and a good sense of direction, it is not necessarily an easy place to navigate. And for the visually impaired, the challenge is even greater. So, this month, a unique voice navigation field experiment led by civil engineering and general contracting firm Shimizu Corporation, IBM Research and real estate developer Mitsui Fudosan is taking place in an underground pedestrian walkway and COREDO Muromachi shopping park buildings 1, 2, and 3 in Nihonbashi-Muromachi, a popular downtown district with history that dates back to the Edo period of the 1600s.