To find products efficiently first I'll recommend you to select your preferred language, currency and shipping country. And then narrowing down the categories. If you fail to select the shipping country search will include domestic only store and will be hard to reach overseas shipping store. If you are going to arrange forwarding services. Choose "Japan or Use Forwarding service" on the Shipping county the search will go through all the products on Rakuten Global.
To help you to buy stuff direct from Japan through Japan's largest and well known online shop Rakuten and amazon.jp