JR Pass or Hokkaido Pass?

Hi there,

I'll be travelling to Osaka and Hokkaido in Dec, spending 5 days in Osaka and 9-10 days in Hokkaido. I'll be landing in Tokyo and travelling to Osaka, then fly to Hokkaido. I'm wondering if I should buy a 14-day JR pass (nation-wide) or a 7-day JR pass (nation-wide) + 7-day JR pass (Hokkaido). Which will be a better choice? Will the Hokkaido JR Pass allow me to board the subway? or will the nation-wide JR Pass allow me to board the JR buses in Hokkaido? Thank you for anyone's help!