The South Korea Motorcycle Shipping and Ferry Guide
Here's a packed new guide on how to ship a motorcycle, car or overland vehicle to and from South Korea. It also includes a detailed guide on how to ferry your vehicle in between South Korea and Russia. If you ferry from Russia to South Korea, you can catch the easy ferry from Busan to Japan.
Here's the South Korea guide: https://www.madornomad.com/the-south-korea-motorcycle-shipping-and-ferry-guide/
And here's how to get the ferry from South Korea to Japan: https://www.madornomad.com/how-to-catch-the-ferry-from-japan-to-south-korea/