Newly added system jpnsks contains all the physical shinkansen lines. The shinkansen-only rail lines, not the services. Because infrastructure is the basis, there are no concurrencies, plus the Akita and Yamagata mini-shinkansen lines are not included because they have no unique-to-them shinkansen-only rail.
Shinkansen lines are actually owned by one or more members of the JR Group. I chose to separate them out so that they would not be spread across five systems.
I looked through the various railway data threads and to me it seemed that the infrastructure vs service choice isn't completely settled. Should I continue using infrastructure for jpnsks, or switch to service? Visitors use services, Japanese railfans use infrastructure - what is our target audience?
For the Japanese railfan perspective, see
https://www.noritsubushi.org/ - a web site where >50K users track their rail travels in Japan. Noritsubushi translates to Ride Samurai / Ride Warrior. Currently 812 people have ridden all the JR lines and 149 have ridden everything. Japanese railfans usually track their travels based on rail line. If they track a service name, it is decomposed into its component rail line segments. Because of this there are almost no concurrencies in their tracking.