Pick up a load of Food Rations for the trip, and sell them at the end.
Time to see how the other half lives. There's not much in the Chugoku system, just Kyoto Base and jump holes to Hokkaido and Honshu. Hokkaido is worth a visit, though, at least for the derelicts.
Things in Hokkaido:
If you go by Ainu Depot, pick up a load of Cardamine for Mission 10.
When you're done, head back to Kyoto. You're now Level 16, and can buy Class 6 equipment; upgrade your shield before you head out again. You may also want to swap Dublin Dusters for the Sunfury 2s.