From Tokyo, take the train to Akita City. Transfer to a local train south to Ugo Honjo. (Both fares included in JR pass).

At Ugo Honjo transfer to the Chokai san line for Yashima (terminal station).

The ￥600 fare is paid when arriving to Yashima (cash only). You may have just a few minutes to transfer at Ugo Honjo. Do not worry, the station is quite small. The train to Yashima is usually on the other track (and may have only one carriage.)