Hi Henry (and All members),
My name is Jean and I have been lurking on this site for quite a while before joining. I am 54, living in France (Paris) and have been collecting Nihonto for 3 years.
To answer your question, it is not Jinkei but Junkei. He is a smith of Bizen Province ans is rated Sai jo, He was active during Ko-An (1278 AD)
You can find him in Hawley "Jun 2" or in the Fujishiro K 503
Jean Laparra