chinese & japanese

This lovely hand painted oriental plate was made in Japan then shipped to Hong Kong to be painted by the chinese (aparently) for export in the 1950s, it is 13" across and in A1 condition , it has a mark on the bottom 'overjoy hand painted in Hong Kong' in a circle with a chinese junk in centre..its very heavy for its size..
This plate rises in the centre as you can see in one on my pics it also has a dull cream sponged look on the picture side, the back pure white ..when I saw it in a second hand shop I just had to have it £5.
After looking this plate up on the web I would say its one of the nicer pieces from this company as most are multi coloured and more flowery newer looking designs..
any info will be much appreciated