Shinkansan short trip from Tokyo

I have looked at the info on the Shinkansan but can't find what I need. We would like to do a day trip on the shinkansan from Tokyo to see a little of the countryside, any recommendations would be appreciated.

First, it's Shinkansen. ;)

There are plenty of nice countryside places reachable from Tokyo by Shinkansen, my personal favourite being lake Tazawa.

http://www.japan-guide.com/e/e3657.html

How about Karuizawa?

http://www.japan-guide.com/e/e6030.html

This is about a 70 minute Shinkansen ride from Tokyo, and it is a Shinaksen Station.

For a day trip from Tokyo with an active JR Pass, I would also recommend Matsushima Bay and the Zuiganji Temple.

http://www.japan-guide.com/e/e5100.html

This is a very nice boat ride around some very interestingly carved Islands. Matsushima Bay is ranked as one of the three most scenic views in Japan.

I like Karuizawa too. There are some great places to eat there, and a good hike (bushwalk) to Usui pass (border Gunma/Nagano) with great views, just near a temple (cant remember the name but the icon is the 3 footed crow) and the most awesome dango place ever. It starts from the top of the Ginza street.

The shinkansen is awesome, too. It is the Asama, and if you splurge and go green car it is really nice inside.

Not really country side but still off the beaten track, If your going to be in Japan Nov-March maybe Nanaba No Sato in Nagashima, Nagoya. Just recently came back from going and the lights are awesome! http://www.japan-guide.com/blog/scott/121127.html

When?

Thank you for your help thus far and sorry about the misspelling!! I will look into the trips suggested.
We are planning on traveling in Mid April.
cheers.

Funaoka[船岡] recommend.
http://www.town.shibata.miyagi.jp/index.cfm/69,0,73,211,html
All Sakura[桜：さくら] trees Top1 viewing spot of South Tohoku area.
But full blooming[満開(man-kai)] timing date not flat.
Senbon[千本] means a thousand trees amazing riverside.
One of Top 100 Sakura selection in Japan(nation wide).
http://oogawara.com/sakura.html

Directions: http://goo.gl/maps/RBS8M
Take fastest Shinkansen "Hayabusa" in Japan max:320km/h until Sendai
then back by local train until JR Funaoka sta.
Buy a "Japan Rail Pass" or "JR East pass".
http://www.japanrailpass.net/eng/en001.html
http://www.jreast.co.jp/e/eastpass/

Don' t forget full charged camera batteris :)
https://www.flickr.com/photos/sonotoki/14141691301/
http://ciao66.exblog.jp/21782030/