Tokyo--VerticalNet Kabushiki Kaisha, a joint venture between Horsham, Pa.-based VerticalNet Inc. and Tokyo-based Softbank E-Commerce Corp., will introduce a series of vertical b-to-b communities aimed at Japanese corporations. They will be modeled after the communities in VerticalNet's U.S. site. Further details were not disclosed. VerticalNet has also tapped David Kostman, formerly a managing director at New York-based investment bank Lehman Brothers, as president of VerticalNet International, VerticalNet's non-U.S. division. He will oversee VerticalNet's interests outside the U.S. About 40% of VerticalNet's site traffic comes from outside the U.S.