Unless you follow Nick Komiya, at Warrelics, you probably haven't EVER heard this before!
Nick has translated a regulation change, dated August 1940, that specified the all-brown tassel for use by the enlisted equivalent of the Gunsoku, civilian officials, both the Ko-in (lance corporal) and Hanin-ko (NCO). This is in conflict with the info in Dawson's book which called it a "Late war" IJA officer tassel; however Dawson doesn't cite his source. I've used the email published in his book to