According to Google Maps, you need a Jet Ski to get to China from Japan and will require one for the return trip too.
Google advises that you take the 486 mile (782km) trip across the Pacific Ocean by Jet Ski. The route Includes tolls and a ferry.
We are wondering when Google will update its trip advisor to read:
This route has tolls.
This route includes a ferry.
This route includes a Jet Ski.
Try it for your self.
1. Go to Google maps
2. Go to “get directions”
3. Type Japan as starting point
4. Type China as ending location
5. Read direction #43
in reverse, Read Direction #42