Finding Importers for marble, granite, tiles and other related special construction and landscaping Stones

Hi All,

I am currently working in Japan but would like to start a small business of importing marbles, granite, slatestones, tiles, veneer and such products and sale in Japan. I have a strong sourcing capability as my family business is already exporting to over 100 countries from my home country.
I am looking ways to find leads of potential importers or agents or BTB portals (similar to Alibaba or so) etc where I can find the requirements and possibly connect with relevant importers.
Anybody has ideas, thoughts etc on how to go about it?