I've made a printable Japanese Merchant Recognition Manual, primarily because I have had a hard time deciding exactly which ship I'm looking at while trying to flip through the pages of the in-game recognition manual. I've grouped these with similar looking ships on the same page to help determine what you're seeing through the periscope.
Here's an example page:
There are two version, one in Imperial and another in Metric.
Imperial:
http://files.filefront.com/ONI+Merch.../fileinfo.html
Metric:
http://files.filefront.com/ONI+Merch.../fileinfo.html