MAEBASHI--A time-honored soy sauce business in Gunma Prefecture has launched a project to age bottles of its sauce in the old Shinetsu Line tunnel in Usui Pass, which lies in central Japan between the prefecture and the neighboring prefecture of Nagano.... The company, Aritaya, plans to leave the soy sauce in the tunnel for a year to mature, and hopes to convert its project into a tourism-boosting resource.... The soy sauce being used in the project was created from soy beans and wheat produce