[samokan]

actually you can take the JR line to JR Ochanomizu station.

Jimbocho and Ochanomizu district are beside each other.
Take the south exit in ochanomizu and walk along meiji avenue passing by meiji university. that avenue runs all the way to jimbocho , i think its just about 10 minutes walk.

or take the JR train all the way to Yurakucho station.
and take the subway Mita line ( Hibiya station ) to Jimbocho.