Japan-Rail.net

The winter Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, can be used from tomorrow, until January 20.
More details on the Seishun 18-kippu are here.

The winter Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, is on sale from tomorrow. It can be used between December 10 and January 20.
More details on the Seishun 18-kippu are here.

The summer Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, can be used from tomorrow, until September 10.
More details on the Seishun 18-kippu are here.

The summer Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, is on sale from tomorrow. It can be used between July 20 and September 10.
More details on the Seishun 18-kippu are here.

Yes, it is. The ferry is to be spun off into a subsidiary company of JR West from April 1st, 2009, but even after this date Seishun 18-kippu tickets will continue to be valid.

The spring Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, can be used from tomorrow, until April 10.
More details on the Seishun 18-kippu are here.

The spring Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, is on sale from tomorrow. It can be used between March 1 and April 10.
More details on the Seishun 18-kippu are here.

The winter Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, can be used from tomorrow, until January 20.
More details on the Seishun 18-kippu are here.

The winter Seishun 18-kippu, a ticket for unlimited (albeit with restrictions) travel on JR lines, is on sale from tomorrow. It can be used between December 10 and January 20.
More details on the Seishun 18-kippu are here.