It wasn't always the case, but Ryukyu is one of the easier OPM starts. They can expand under the protection of Ming, there are no immediate threats, and Okinawa starts next to the richest corner of the world. Still, an OPM WC presents many challenges, especially on Very Hard.
A typical WC during the first two hundred years should focus on building a strong economy and filling key idea groups. Conquest is costly without administrative efficiency. Early game expansion should be limited to securing valuable land. The most valuable land and the most vulnerable targets near Ryukyu lie in Southeast Asia. The region will serve as our foundation for the first half of the run.