Sleeper to Hokkaido

When will the Cassiopeia train stop running?
Can we book online?
Thanks

I think you can only book one month ahead and then it might sell out on day 1 - we looked at it a while ago, but decided for the price, we could better spend our money doing other things.

Planned withdrawal is Spring 2016 so probably a year away.

It was supposed to stop running this April, but in fact they have maintained it with no end in sight currently.
No, you can't book online.

Ah, no, it was the Hokutosei which was supposed to stop running, nothing was announced for the Cassiopeia.

The Cassiopeia is expected to be discontinued with the spring 2016 timetable revision together with the Hamanasu Express.

I heard that the Hokutosei will have its last run as temporary train in August 2015.

The Cassiopeia books out quickly, and I think one reason for it is that travel companies get a large share of compartments (for inclusion into their tour packages). I think the compartments go back on sale in case the agencies don't sell all of them by a certain date. But I am not sure.

In other words: if the Cassiopeia is sold out, a) vacancies may become available again as the travel date nears and b) you may be able to ride it, nevertheless, by purchasing a travel package through a travel agency. Unfortunately, a lot of these travel agencies may not have English speaking staff (or websites). Here is one of the agencies' websites about tours that include the Cassiopeia:
http://www.hankyu-travel.com/kokunai/train/cassiopeia.php

Thanks for the travel agency suggestion!