From Otsuka to Tokyo Shinkansen

Hello!

Just wondering should I take Yamanote line from Otsuka to Tokyo or Marunouchi subway line Otsuka to Tokyo when I�Lm going for Shinkansen to Kyoto?

Maybe subway is less crowded? Planning to take Shinkansen at morning, around 10am

Maybe, there is no more of the Marunouchi line is crowded.
However, transfer might be a little inconvenient.
http://www.jreast.co.jp/e/stations/e1039.html
You switch in the Marunouchi underground central gate.
https://www.youtube.com/watch?v=L5K7RMAmRbU

Tokaido Shinkansen has two stations in Tokyo Metropolis: Tokyo Station and Shinagawa Station.
All Tokaido Shinkansen trains make a stop at Shinagawa Station, which is the second station after Tokyo Station for westbound trains.

When you use Tokaido Shinkansen from Tokyo Station, please note that JR-Central and JR-East have the Shinkansen zones separately.
In Tokyo Station, you can pay attention not only to the word "Shinkansen" but only to the name of the Shinkansen line, and follow signs for Tokaido Shinkansen, which is operated by JR-Central.
In Shinagawa Station, only JR-Central has a Shinkansen zone.
- Map for Tokyo Station of JR
http://english.jr-central.co.jp/info/station/_img/tokyo_L.jpg
- Map for Shinagawa Station of JR
http://english.jr-central.co.jp/info/station/_img/shinagawa_L.jpg
- Typical icon for Tokaido Shinkansen
http://commons.wikimedia.org/wiki/File:Shinkansen_blue.png

You can
either take a Yamanote Line train on the outer loop from Otsuka Station: Track 2 to Track 5: Tokyo Station for about 20 minutes
or take a Yamanote Line train on the inner loop from Otsuka Station: Track 1 to Track 1: Shinagawa Station for about 30 minutes,
and then pass a Shinkansen transfer gate to the Tokaido Shinkansen zone.

Tokyo Metro does not have Otsuka Station.
If you use Tokyo Metro Marunouchi Line from Shin-Otsuka Station, please note that the entrances and the platforms differ by directions. (To change platforms there, you need to use staircases.)
You can
take a subway Marunouchi Line train from Shin-Otsuka Station: Track 2 to the next Ikebukuro Station,
make a short transfer to JR,
take a Yamanote Line train on the inner loop from Ikebukuro Station: Track 6 to Track 1: Shinagawa Station for about 30 minutes or less
and pass through a Shinkansen transfer gate to the Tokaido Shinkansen zone.
Alternatively you can take a subway Marunouchi Line train from Shin-Otsuka Station: Track 1 to Tokyo Station, make a transfer to JR and pass through a Shinkansen transfer gate, but the route from the Tokyo Metro platform is long both vertically and horizontally.

Thanks for the info guys!
My mistake, remembered wrong about the Marunouchi line, shin-otsuka station is almost 1km from our hotel so we�Lll take the Yamanote line from Otsuka.

Hmm, Shinagawa sounds way easier and more hassle free transfer and it�Ls only 10min more on Yamanote so I think we�Lll go for that :)