Blue and White Small Square Plates Arita/Imari, Japan

I purchased several of these small square plates in Arita/Imari, Japan in 1983 or 1984 at the end of the pottery season. I would like to know more about them and purhaps purchase additional pieces. I have searched on-line but have not been able to find any information or other dishes with a similiar pattern. Any information would be greatly appreciated.