>> "Goods for personal use that were purchased abroad with a total market value not exceeding ￥200,000" was considered duty-free.
Only if you are leaving the stuff behind in Japan. Most countries (including Japan) allow you to bring reasonable amount of personal effects with you (with no specific value limit) when you enter the country duty free, as long as you take them with you when you leave.
If you are bringing a lot, they may suspect that you plan to work in the country, or you plan to sell/gift them away. It's up to you to prove your purpose of visit, and why you need that much equipment.
You can learn all these from watching those reality "border security" TV shows.
>> can anyone offer any insight on what I should be declaring?
Only stuff you plan to leave behind when you finish your trip.
In some countries, such as China, bringing that much equipment will be problematic because they think you are a journalist(big red flag) and you don't have the proper visa. In Japan they may or may not think you are going there to work.
Last edited by beep88; Feb 11, 2016 at 12:48 pm