Shinkansen Reservations

My husband and I will be arriving in Tokyo on 3/14/15 and would like to take the shinkansen from Tokyo to Kanezawa on 3/15/15. As this is the first day this line will be open, we are nervous about waiting to get tickets until we get to Japan and would like to purchase reserved seats ahead of time. So far, three different travel agencies and much online searching have not revealed a way to accomplish this.
Anyone know how we can get these tickets?

Not Kan[e]zawa Kan[a]zawa.

Maybe seat booking impossible by train fans booked already.
Sales starts one month before.(No online booking from out of Japan)
But not sure all trains full booked or not on the day
bc depends on weather conditions(by snow) really bad or not.
(if bad booking cancel a lot)

However,all trains with un-reserved seat cars about 340 seats total as 5 cars of 10.
No need seat booking.

Considering there is no schedule for that service right now, it's going to be hard to make reservations for a non-existent train. I need to take the Kanazawa to Omiya portion of that new service, but I'll have to wait until a schedule comes out to even try to think about reserving it before I get there in April.