Originally Posted by ksandness

In both Tokyo and Osaka there are JR commuter lines: the Yamanote, Chuo, Joban, Keiyo, and Sobu Lines (maybe some others that have slipped my mind), and in Osaka, it's basically the Kanjo Line, which circles the central city plus a few lines that go out of town.

However, the subway runs to more destinations than the JR Lines do in both cities.

Getting a Suica card or other ticket debit card will not save you any money, but it is very convenient not to have a buy a ticket for each trip, as we did in the old days.