Seishun 18 Kippu Hokkaido Shinkansen Ticket

Hello.
I plan to travel from Honshu to Hokkaido using Seishun 18 kippu, so I buy "Seishun 18 kippu Hokkaido Shinkansen Ticket" for 2300 yen. It's valid for Okutsugaru-Imabetsu to Kikonai (Shinkansen), and Kikonai to Goryokaku (South Hokkaido Line).
My question is:
1) Aside of "Seishun 18 kippu Hokkaido Shinkansen Ticket", do I need to buy another ticket for seat reservation? Is there any chance that I can't ride the Shinkansen because the seat is full?
2) I plan to go to Hakodate instead of Goryokaku. Can I just take the same train (since Hakodate is the terminus) and pay the extra fare (210 yen) when i reach Hakodate? Or I don't need to pay?
Thank you very much.

Link to said ticket/pass? I cannot find anything named "Seishun 18 Kippu Hokkaido Shinkansen Ticket" using google. Or any pass remotely close to what you are describing.

Since no limited express services go through the Seikan tunnel anymore. My understanding is that you just buy a regular shinkansen ticket from the top of Tohoku to Shin-Hakodate-Hokuto, then just get a local train into Hakodate.

It is described for example here: http://www.jreast.co.jp/tickets/info.aspx?txt_keyword=18&mode=keyw&Sea...

For the Shinkansen part, you can just sit on any free seat (you will not get an assigned seat). In the (very) unlikely event that the train is fully booked and all the seats are occupied, you just stand.

For the South Hokkaido Railway part, yes, you can go to Hakodate by paying the fare from Goryokaku to Hakodate (210 yen).

hakata14: Since the ticket is new, perhaps there are not really many information about this ticket. But japan-guide already give a brief explanation. I can do like what you suggested, it's more practical, yet also more costly. So i choose to buy the 18kippu-Hokkaido shinkansen instead.

Firas: I will go during Obon season, so it will be packed. What i want to know is whether there's a possibility of rejection due to the full seat. Based on your explanation that I don't need to reserve the seat, I assume it's safe to say that I can ride the shinkansen regardless whether the seat is fully packed or not. So everything is OK already. Thank you very much!

Yes the 2300 yen option is better cost wise. I read the japan-guide write up about it, and it says you can take the South hokkaido Railway all the way to Hakodate?

I don't think it really matters though as if you are using one of your seishun 18 tickets days, it would cover this small last section.

Just a head up that all shinkansens do no stop at Kikonai Station. I counted 4 of the eleven regular trains not stopping there.

I will go during Obon season, so it will be packed.

No, it will not. You can look up seat availabilities yourself if you want. https://www3.jrhokkaido.co.jp/rail-en/asp/RWY010.aspx

Just a head up that all shinkansens do no stop at Kikonai Station. I counted 4 of the eleven regular trains not stopping there.

That doesn't really matter here because if a train does not stop at Kikonai, it does not stop at Oku-Tsugaru-Imabetsu either. http://www2.jrhokkaido.co.jp/global/english/ttable/08.pdf

haha Good pick up. I didn't even think of that.

Actually, I think the Seishun should cover you between Goryokaku and Hakodate, since it's on a JR line, so there should be no need to pay the extra 210 yen (at Hakodate station you just show your Seishun as usual to exit, since it's a JR station).

"japan-guide.com" is NOT railways company's official.
Ticket name is "Seishun 18 kippu Hokkaido Shinkansen Option Ticket(-ken/JP)".
Don't forget "Option/オプション" part when ordering.
http://tr.twipple.jp/imgp/5c/1ea6db.jpg
Purchasing possible any area's JR stn
at ticket office/counter "midori no madoguchi/みどりの窓口".
http://tabi.jiyujin.tokyo/okutsugaru-imabetsu/
Midori means just "green" (but "yellow-green" using mostly).
http://5353.cocolog-nifty.com/photos/doblog/fi2623428_1e.jpg
Saying "18" is "eighteen" in EN is right/no problem
If would like to say in JP use "jyuu-hachi".
http://www.learn-japanese-adventure.com/image-files/t2-japanese-number...
https://youtu.be/KPUC8OKEWA8

Back to main Qs,
1)
If book ordinary reserved you have to pay all
"base fare(stn A to B) 1450Y" and "LtdExp reserved seat fee 2710Y"
total 4160Y/adult oneway. (18 kippu invalid)
(Green and GranClass more expensive check by yourself use "HyperDia" if need)

Now checed obon weeks(btw 11 to 16) seat booking condion
but all train are not full seems enough numbers
only one train "Hayabusa 13" a few seats left on 11.
No need sign in of JR Hokkaido member ship.
http://www.jr.cyberstation.ne.jp/vacancy/Vacancy.html

Okutsugaru-Imabetsu/奥津軽いまべつ stn placed a bit far
fr Tsugaru-Futamata/津軽二股 stn but not so far no worry.
http://www.jrhokkaido.co.jp/network/barrier/108/okutsugaruimabetsu-map...
https://en.wikipedia.org/wiki/Tsugaru-Futamata_Station
"EN wiki" map two wrong (just published yet)
"Kaikyo line" part is now "Hokkaido Shinkansen,Kaikyo line".
"Tsugaru-Imabetsu(JR East)" is now "Okutsugaru-Imabetsu(JR Hokkaido)"
management railway company changed fr Hokkaido Shinkansen open date.

2)
No need 210Y.
BC Isaribi Railway(not JR) end station is Goryokaku
but btw Goryokaku and Hakodate is JR's line 18 kippu covered.
Just using Isaribi Railway car no need get off at Goryokaku.


BTW,which stn starts? where to go? how many days?
If thinking going far fr Hakodate very inonvenient only by 18 kippu
bc Local/普通 trains operate numbers are not enough.
http://ekikara.jp/newdata/ekijikoku/0101011/down1_01202011.htm
(click each trains time except 特(LtdExp) in Red)
https://en.wikipedia.org/wiki/Hakodate_Main_Line
Using "HyperDia" faster but.
"Hokkaido & Higashi-nihon Pass",too.
http://homepage3.nifty.com/gogo-happytrip/passinfo/en.html