Sotetsu-Tokyu Link enables through running to Tokyo
https://www.railwaygazette.com/passenger/sotetsu-tokyu-link-enables-through-running-to-tokyo/63789.article
I think that Sotetsu no longer needs to run through JR Lines, because most of the JR lines where Sotetsu train runs through are paralleling with Tokyu Toyoko Line, Tokyo Metro Fukutoshin Line, and Tobu Tojo Line.
