A little info, Von Epp was assigned to the 4th East Asian Infantry Regiment in 1900, so at least one regiment existed for some purpose. This was in China.
http://216.239 ]http://216.239.37.104/search?q=cache:QJQJV5_fb0cJ:www.thirdreichforum.com/viewtopic.php%3Ft%3D7915%26start%3D0+%22east+asian+infantry+regiment%22& hl=en&ie=UTF-8]http://216.239[/UR L] .37.104/search?q=cache:QJQJV5_fb0cJ:www.thirdreichforum.com/viewtopic.php%3Ft%3D7915%26start%3D0+%22east+asian+infantry+regiment%22& hl=en&ie=UTF-8
also see-
http://motlc.wiesenthal.com/text/x07/xm0701.html
Now that I have established that the East Asian Infantry Regiment(s) actually existed and the grip marking might stand for that it still does not explain the 'J'. In Nolls book he indicates that J.R. stands for Infantry Regiment and Jager Regiment and that the J. stands for Jager-battalion
those are not compatable with this stamping.