As Jareth says this is a late war Amy sword. One needs to be careful with some of the old reference books as they can contain information that wiht the passage of time has been proven incorrect.

Jim Dawson's updated reference book is a great source of information ...

SWORDS OF IMPERIAL JAPAN: 1868-1945
CYCLOPEDIA EDITION
J.Dawson (2007)

and can be purchased here if one so desires ...

http://www.satcho.com/References.htm

scroll down to see photo.

Regards
Stu