Japan has changed over the years and many of the ingredients I need for baking are easily found here. There are many good baking supply stores which carry fruit purees, nut powders, and excellent chocolate and I often use these in my recipes. Everyone will have access to different ingredients depending on where you live so sometimes substitutions must be made.
I have my favorite stores mapped out around Tokyo for quick shopping. I also use Internet shopping for big purchases that I don't want to carry. Deliveries are made 7 days a week so it is hard to pass up this convenience.
I have converted to using metric measurements for my recipes instead of cups, etc. You can check this site for conversions. Weighing ingredients really is much simpler and faster.