Paul,
Since China is the size of the 48 states of the US and Japan is a very long island, could you be more specific as to what cities you are currently visiting? I think people would need to know what you will be near.
Also in China, just because something looks close don’t think that it is. It takes at least twice as long, in China (Especially southern China), to cover the same distance as it would in North america or Europe.