As explained in the article below, Shinkansen is very crowded during year-end and new year peak period.
Book NOW!! 2017 Year-end and 2108 New year PEAK is approaching!
https://shinkansen-ticket.com/blogs/news/year-end-and-new-year-peak-is-approaching-book-now-and-securely-reserve-your-seats
Some Shinkansen tickets are already SOLD OUT.
Here are the tickets already SOLD OUT as of December 13th, 2017.
JR (the train company) website has been intermittently very slow due to heavy traffic. The other tickets can be sold out very soon.
Please order as soon as you decide your schedule. We will do our best to reserve the left tickets though we can not guarantee your ticket reservation. We will refund 100% in case we can not reserve your tickets.
You can book Shinkansen/Bullet train tickets online here. We purchase tickets for you and deliver to your hotel. Reserve your tickets/seats without the hassle.