Unreserved Seats on Shinkansen

We are travelling from Tokyo to Kyoto on January 2016. If we buy unreserved seats tickets, will everyone get a seat? Or we may have to stand if the train is fully booked?

Reserved and unreserved seats are in different cars, so the status of reserved seats does not influence the avalability of unreserved seats. Unreserved seats are first-come, first-served, so if you arrive early enough to be in the front of the line, you will get a seat.

There is no guarantee you will all find a seat. You can increase your chances by boarding the train at a station closest to the start of the run, such as Tokyo Station and queue up as quickly as you can on the painted lines on the platform immediately after the previous train has departed from the track.

Some stations (like Tokyo) have lines for the current and the next train so there might be two queues. Knowing where to stand and wait (arriving a little earlier) helps.

Thank you all for the helpful info. From what I understand now, unreserved seat ticket does not guarantee a place to sit so we may have to stand for the whole journey unless we go to the station very early to queue. We are travelling in end January during winter, I guess it is low season for tourist, maybe it will be easier to get a place to sit ? Or the train is still always full ?

Since they don't sell a specific number of unreserved tickets for the Tokaido Shinkansen for a given day, there's no way to determine how many will board any one particular train.

If you are traveling to Kyoto from Tokyo and are not using the JR Pass, you have access to all train services leaving the Tokyo area (Kodama, Hikari and Nozomi). That is quite a number of trains! There are two stations in Tokyo that serve as a stop for the Tokaido Shinkansen: Tokyo (Terminus) and Shinagawa.

If I were you, I would use Tokyo Station to queue up. Each unreserved car has an access door at either end of the car. Once you're in the queue and the "all clear" is given to board the train, it's pretty much "first come, first serve." If you all are queued up together, the chances of getting seats next to each other are quite high.

For those unreserved seats left over, if any, from the embarkation at Tokyo Station, the passengers who board at Shinagawa (the following station) will take the remainder and then it's off to Shin-Yokohama and stations further along the line. IPeople will start to stand if the train is full and popular. I don't know what the maximum capacity is, if there even is one. I always take the reserved cars as I usually travel with a JR Pass and it's free to reserve.

Not all trains get filled up, requiring you to stand all 2.5+ hours of the ride. Some people get off at Nagoya, etc. But at the time of year you mention, I don't think you'll have many problems securing seats for all of you together. Try to get them on the right side of the car in the direction of travel, as those are the ones with a view of Mt. Fuji (if visible).

Hi John, thank you so much for the details. we don't mind not sitting together, we just wanna to secure a place to sit. With your advise, I think we can buy unreserved tickets and save some budget. Thank you again.

Check out Platt Kodama.
Cheaper, reserved seats. The downside is that it's a Kodama train so it takes about 4 hours to get to Kyoto (it stops at all stations), compared to the 2 hours on the Nozomi. But it's like 4000 yen cheaper!