It's 17 minutes away by train from the "big" city of Kamaishi.
From Morioka you can either take a train or a bus. The train leaves around 2:30PM and 4:20PM and takes either 2 1/2 hours or 3 1/2 hours, depending on if you have to wait in Hanamaki. This costs about ¥2,500.
The bus leaves from in front of Morioka Station at 4:20PM. This also costs about ¥2,500.but this goes just to Kamaishi, where you get off the bus in front of the station and take another 20 minute bus to Otsuchi (the correct buses are 浪 orã赤æµ.