7 days JR Pass price is almost same as round trip fare between Tokyo and Osaka by Shinkansen. That means if you have one way trip from Tokyo to Osaka or reverse, JR Pass is not worthwhile using. However if you add some trips when you stay in Osaka and Tokyo, you may use JR pass 7 days.
***Twilight Express was discontinued in 12 March, 2015. There is no overnight train option between Osaka and Hokkaido any more.***
Twilight Express is very popular. Many tourists might think about taking this luxury overnight train. But you have a problem. Twilight Express cannot be reserved online. The only way to reserve it from outside of Japan is calling Odekake net 078-341-7903 in Japanese and you have to pick up your ticket in JR West, Shikoku or Kyushu stations. You cannot pick up it in other areas, like Tokyo. Otherwise You need to go to a reservation window at the station in Japan. Ticket is started to sell one month prior to the departure date. That means it may be sold out when you arrive in Japan. So you need to think about alternatives if you have a plan to take this train. I tell you several options for the case that you cannot make Twilight Express.
Tokaido Shinkansen is the oldest and busiest Shinkasen line and it is operated between Tokyo, Nagoya, Kyoto and Osaka. Sanyo Shinkansen is operated between Osaka, Okayama, Hiroshima and Hakata (Fukuoka). Both lines are connected each other. Many trains, “Nozomi” that is the fastest train on Tokaido-Sanyo Shinkansen, run from Tokyo to Hiroshima and some of those run to even Hakata.
Most of Hikari run between Tokyo and Shin-Osaka, But some of those run to Okayama and Hiroshima.
Sanyo Shinkansen connected to Kyushu Shinkansen at Hakata. Many trains, Mizuho and Sakura are operated between Shin-Osaka and KUmamoto or Kagoshima-Chuo directly. Please see the post, Kyushu Shinkansen to get details.
Sanyo Shinkansen is operated between Shin-Osaka and Hakata. But Sanyo Shinkansen is connected with Tokaido Shinkansen (from Nagoya, Kyoto and Tokyo) at Shin-Osaka and Kyushu Shinkansen (from Kumamoto and Kagoshima) at Hakata.
Most of trains run from Tokyo (Nozomi and Hikari) are operated by Tokaido Shinkansen fleet, 700 series or N700 series. If you look for the images of these trains, please see Tokaido Shinkansen image gallery.
We cannot think about the travel in Japan without Shinkansen. Especially Tokaido Shinkansen (Tokyo-Shin Osaka) can be used for transfer to Kyoto and Osaka from Tokyo. Most of travellers take this Shinkansen once or more. Probably you want to see the interior of Shinkansen trains. There are several types of trains to be operated on Tokaido Shinkansen. I show you all types of trains of Tokaido Shinkansen trains. And also most of Tokaido Shinkansen trains go through on Sanyo Shinkansen between Shin-Osaka and Hakata. So if you take Sanyo Shinkansen, this post may be useful for you too.
*This deal will be sold until February 28, 2015 and can be exchanged until May 31, 2015. On March 1, 2015, this deal, Sanyo Area Pass will be replaced by Sanyo Sanin Area Pass, Kansai Hiroshima Area Pass and Hiroshima Yamaguchi Area Pass.
This pass covers Kyoto, Osaka, Kobe, Himeji, Hiroshima, Miyajima and Hakata. You can take any trains in the coverage area with a few exception. If you will be a temporary visitor, you are eligible to purchase this deal.
If you have round trip from Osaka to Hakata, this pass is much cheaper than single fares. But if you travel outside of Kansai area or just go to Hiroshima, you may consider other deals.