I plan to buy ICOCA in Osaka and use it in Kyoto, Tokyo, Kawasaki and Yokohama. Is this IC card usable in metro lines in those cities? And is it useable for intercity train from Tokyo - Kawasaki - Yokohama (like Keikyu line, etc.) and return? Basically yes.
If you have never used an IC transportation card in Japan, please check "Basic Use" in this article.
http://www.japan-guide.com/e/e2359_003.htmlAn ICOCA Card can be used
on JR-West sections around Osaka and Kyoto Stations,
on non-JR bus lines and railroad (including subway) sections inside the PiTaPa network in Kansai Region,
also on most JR-East and non-JR railroad sections (including all subway lines) inside the Suica-PASMO network in and around Kanto Region.
Among railroad lines where Suica Cards and PASMO Cards can be used,
ICOCA Cards are not yet accepted on Yokohama Seaside line in Kanagawa / Tama Monorail line in Tokyo / Chiba Urban Monorail lines in Chiba / Kanto Railway [Kantetsu] lines in Ibaraki.
Regarding Tokyo Subway Network, "Metro" usually refers to Tokyo Metro lines only. "Subway" is used as a general term for Tokyo Metro and Toei subway lines.
In Kawasaki City, no subway line is available, but there are many stations on JR and non-JR lines. Railroad accesses to places in Kawasaki City vary depending on their locations.
You cannot use Shinkansen with any IC transportation card.
(e.g. Tokaido Shinkansen: Shin-Osaka -- Kyoto -- Nagoya -- Shin-Yokohama -- Shinagawa -- Tokyo.)
Fuji Kyuko [Fujikyu] line (connecting Otsuki and Kawaguchiko) in Yamanashi is not yet ready for IC transportation cards.
In Kyoto City, IC transportation cards are not yet accepted on Kyoto City Bus lines, Kyoto Bus lines or Enoden Electric Railway lines.
A Kyoto City Bus - Kyoto Bus One-day Pass (500 yen per adult (roughly over 12), 250 yen per child (roughly 6 to 12)) can cover bus rides to/from many major tourist spots in Kyoto City. This bus pass pays off in three or more bus rides in a day inside the fixed-rate zone, where a regular bus fare is 230 yen per adult per ride.